Disney couldn't care less about what ride is represented in what park. If it gets enough people by Disney's metrics it stays, unless they decide they want to MB the attraction in question. I think that's more of a fannish "rule" than anything else. Like when coaster enthusiasts said that you "couldn't" turn a stand-up coaster into a normal sit-down looping coaster...only for that exact thing to happen, and happen again, and again...
That said, one factor with Snow White and Pinocchio is that they have higher vehicle capacity than the other FL dark rides, so it's not just alleged unpopularity keeping their lines shorter than the other rides. The rumors could just be people reading too much into that.
Personally, I would shed no tears if Pinocchio left, there's absolutely nothing remarkable about it and I've always been dismayed that it's been cloned twice.
Snow White's removal would be disappointing but honestly, I don't think the ride is good enough OR historically important enough (yes, original three, but otherwise?) that I would stop going if they got rid of it. It's clear to me that modern Disney doesn't regard it as sacred; I don't know that modern guests really do either.
I'm sure at one point Rocket to the Moon/Mission to Mars seemed untouchable too. It's sacred until it isn't.