Smackdown! starts with a recap of Raw, and shows further recaps all throughout the show. Every week. When was the last time you saw Raw recapping anything that happened on Smackdown! the week before? Other than a passing mention from the announcers.
Raw is the 'A' show. It's the flagship. Smackdown! isn't the 'B' Show, that's Main Event, but it's not the flagship either. It's somewhere in between.
But...again, we need to remember that title belts are props. It's crazy to me that I've had to explain this three times in the last week or so. They're not real things. It's no different than JBL's cowboy hat, or Jerry Lawler's crown, or Damien Sandow's robe. They don't have any actual real meaning or value. And, no, their lack of value isn't because the WWE doesn't care about them...the WWE doesn't care about them because of their lack of value. And, no, there's not anything they can do about that. It's a terminal condition. When WWE stopped being real, so did the title belts.
It doesn't matter if the WWE WHC is on Smackdown!, or if the US or IC champions are on Smackdown!, or if the Diva's or Tag Team Champions are on Smackdown! because none of the championships matter. You need to look at which wrestlers are on the show, independent of what props they have around their waist or over their shoulder. That's all that matters. And the wrestlers that are on Smackdown! every week are consistent with it being an A-/B+ show.