Okay guys being as we are still questioning the last time, I went to Wikipedia and pulled up the official list of world champions. So the last 5 times the WWE championship was won on Raw was...
1. Cena on July 25th 2011
2. Mysterio on July 25th 2011
3. Miz on November 22nd 2010
4. Orton on June 15th 2009
5. Edge on July 3rd 2006
Now for the second tier world title, the World Heavyweight championship
1. Ziggler on April 8th 2013
2. Del Rio on January 11th 2013 (this was on Smackdown but I'm counting it anyway)
3. Orton on May 3rd 2011
4. Edge on February 15th 2011
5. Ziggler on February 15th 2011
Say you wanted to refer to the last 5 years in this post you're looking at a total of 8 world titles won on free TV. 3 of those were your major world title!
And for comparison sake, in that time period 17 World Heavy weight champions were crowned! Which means 5 of the 17 times the World heavyweight championship changed hands was on free TV! And the WWE championship was won 20 times in that time window, so 3 of 20 times it was won on free tv over the last 5 years. Which if you add them together you're looking at 8 of 37 title changes were on Raw for an average of 21.6% of all world title changes.
Yea it hasn't happened in a while but that is an upward trend, showing they want the world title to mean more than it did when the belt would be won and lost a day later(looking at you Kane and Austin). I do see your point that the belt not being won on Raw makes Raw a smidge less entertaining but it also means you're more inclined to watch the PPV's, so it's a good thing
Also here's the Wikipedia link for it
https://en.wikipedia.org/wiki/List_of_WWE_World_Heavyweight_Champions