Because it didn't. The best way to do this is to split the titles 70 holders into groups. Because not being a stepping stone is a 'new thing' the WWE is doing according to the theory, that group will have only the 10 most recent first time champions. The other groups will have 20 each.
Here's the first 20 different champions:
So that's 4/20 (20%) were future champs, 1/20 (5%) were past champs and 15/20 (75%) were neither.
20 next champions:
7/20 (35%) future WWE Champions, 1/20 (5%) future World Heavyweight Champions 0/20 Past world champs, 12/20 (60%) no championship.
Next 20 Champions
7/20 (35%) future WWE Champions, 2/20 (10%) future World Heavyweight Champions 1/20(5%) Past world champs, 10/20 (50%) no championship.
Most Recent 10 new champs:
2/10 (20%) future WWE Champions, 2/10 (20%) future World Heavyweight Champions, 2/10 (20%) Past world champs, 4/10 (40%) no championship.
So what we see is that in the early days, the title bore little benefit for the future of its holders, but since about 1993, about 40% of IC title holders have gone on to hold a world title, which has been the WWE championship for the vast majority.
So, the situation hasn't changed, take your rose tinted spectacles off. Unless I'm forgetting the time Marvellous Marc Mero was a World Champion.
Here's the first 20 different champions:
1. Pat Patterson - never world champ in WWE
2. Ken Patera - never world champ in WWE
3. Pedro Morales - former world champ
4. Don Muraco - never world champ in WWE
5. Tito Santana - never world champ in WWE
6. Greg Valentine - never world champ in WWE
7. Randy Savage - WWE Champion
8. Ricky Steamboat - never world champ in WWE
9. Honky Tonk Man - never world champ in WWE
10. Ultimate Warrior - WWE Champion
11. Rick Rude - never world champ in WWE
12. Mr. Perfect - never world champ in WWE
13. Texas Tornado - never world champ in WWE
14. Bret Hart - WWE Champion
15. The Mountie - never world champ in WWE
16. Roddy Piper - never world champ in WWE
17. British Bulldog - never world champ in WWE
18. Shawn Michaels - WWE Champion
19. Marty Jannetty - never world champ in WWE
20. Razor Ramon - never world champ in WWE
2. Ken Patera - never world champ in WWE
3. Pedro Morales - former world champ
4. Don Muraco - never world champ in WWE
5. Tito Santana - never world champ in WWE
6. Greg Valentine - never world champ in WWE
7. Randy Savage - WWE Champion
8. Ricky Steamboat - never world champ in WWE
9. Honky Tonk Man - never world champ in WWE
10. Ultimate Warrior - WWE Champion
11. Rick Rude - never world champ in WWE
12. Mr. Perfect - never world champ in WWE
13. Texas Tornado - never world champ in WWE
14. Bret Hart - WWE Champion
15. The Mountie - never world champ in WWE
16. Roddy Piper - never world champ in WWE
17. British Bulldog - never world champ in WWE
18. Shawn Michaels - WWE Champion
19. Marty Jannetty - never world champ in WWE
20. Razor Ramon - never world champ in WWE
So that's 4/20 (20%) were future champs, 1/20 (5%) were past champs and 15/20 (75%) were neither.
20 next champions:
1. Diesel - WWE Champion
2. Jeff Jarrett - never world champ in WWE
3. Dean Douglas - never world champ in WWE
4. Goldust - never world champ in WWE
5. Ahmed Johnson - never world champ in WWE
6. Marc Mero - never world champ in WWE
7. Triple H - WWE Champion
8. The Rock - WWE Champion
9. Owen Hart - never world champ in WWE
10. Stone Cold Steve Austin - WWE Champion
11. Ken Shamrock - never world champ in WWE
12. Val Venis - never world champ in WWE
13. Road Dogg - never world champ in WWE
14. The Godfather - never world champ in WWE
15. Edge - WWE Champion
16. D'Lo Brown - never world champ in WWE
17. Chyna - never world champ in WWE
18. Chris Jericho - WWE Champion
19. Kurt Angle - WWE Champion
20. Chris Benoit - World Heavyweight Champion
2. Jeff Jarrett - never world champ in WWE
3. Dean Douglas - never world champ in WWE
4. Goldust - never world champ in WWE
5. Ahmed Johnson - never world champ in WWE
6. Marc Mero - never world champ in WWE
7. Triple H - WWE Champion
8. The Rock - WWE Champion
9. Owen Hart - never world champ in WWE
10. Stone Cold Steve Austin - WWE Champion
11. Ken Shamrock - never world champ in WWE
12. Val Venis - never world champ in WWE
13. Road Dogg - never world champ in WWE
14. The Godfather - never world champ in WWE
15. Edge - WWE Champion
16. D'Lo Brown - never world champ in WWE
17. Chyna - never world champ in WWE
18. Chris Jericho - WWE Champion
19. Kurt Angle - WWE Champion
20. Chris Benoit - World Heavyweight Champion
7/20 (35%) future WWE Champions, 1/20 (5%) future World Heavyweight Champions 0/20 Past world champs, 12/20 (60%) no championship.
Next 20 Champions
1. Rikishi - never world champ in WWE
2. Eddie Guerrero - WWE Champion
3. Kane - WWE Champion
4. Jeff Hardy - WWE Champion
5. Albert - never world champ in WWE
6. Lance Storm - never world champ in WWE
7. Christian - World Heavyweight Champ
8. Test - never world champ in WWE
9. William Regal - never world champ in WWE
10. Rob Van Dam - WWE Champion
11. Booker T - World Heavyweight Champion
12. Randy Orton - WWE Champion
13. Shelton Benjamin - never world champ in WWE
14. Carlito - never world champ in WWE
15. Ric Flair - former WWE Champion
16. Johnny Nitro - never world champ in WWE
17. Umaga - never world champ in WWE
18. Santino Marella - never world champ in WWE
19. Kofi Kingston - never world champ in WWE
20. CM Punk - WWE Champion
2. Eddie Guerrero - WWE Champion
3. Kane - WWE Champion
4. Jeff Hardy - WWE Champion
5. Albert - never world champ in WWE
6. Lance Storm - never world champ in WWE
7. Christian - World Heavyweight Champ
8. Test - never world champ in WWE
9. William Regal - never world champ in WWE
10. Rob Van Dam - WWE Champion
11. Booker T - World Heavyweight Champion
12. Randy Orton - WWE Champion
13. Shelton Benjamin - never world champ in WWE
14. Carlito - never world champ in WWE
15. Ric Flair - former WWE Champion
16. Johnny Nitro - never world champ in WWE
17. Umaga - never world champ in WWE
18. Santino Marella - never world champ in WWE
19. Kofi Kingston - never world champ in WWE
20. CM Punk - WWE Champion
7/20 (35%) future WWE Champions, 2/20 (10%) future World Heavyweight Champions 1/20(5%) Past world champs, 10/20 (50%) no championship.
Most Recent 10 new champs:
1. JBL - Former WWE Champion
2. Rey Mysterio - WWE Champion
3. Drew McIntyre - never world champ in WWE
4. Dolph Ziggler - World Heavyweight Champion
5. Wade Barrett - never world champ in WWE
6. Ezeikel Jackson - never world champ in WWE
7. Cody Rhodes - never world champ in WWE
8. Big Show - World Heavyweight Champion
9. The Miz - Former WWE Champion
10. Curtis Axel - never world champ in WWE
2. Rey Mysterio - WWE Champion
3. Drew McIntyre - never world champ in WWE
4. Dolph Ziggler - World Heavyweight Champion
5. Wade Barrett - never world champ in WWE
6. Ezeikel Jackson - never world champ in WWE
7. Cody Rhodes - never world champ in WWE
8. Big Show - World Heavyweight Champion
9. The Miz - Former WWE Champion
10. Curtis Axel - never world champ in WWE
2/10 (20%) future WWE Champions, 2/10 (20%) future World Heavyweight Champions, 2/10 (20%) Past world champs, 4/10 (40%) no championship.
So what we see is that in the early days, the title bore little benefit for the future of its holders, but since about 1993, about 40% of IC title holders have gone on to hold a world title, which has been the WWE championship for the vast majority.
So, the situation hasn't changed, take your rose tinted spectacles off. Unless I'm forgetting the time Marvellous Marc Mero was a World Champion.