I think that says more about Disney Imagineering lately in general than re-theming of rides. The appeal of Popeye is the water, you could change out the show scenes with a dozen IPs and it would still work as intended.
But also, the space isn't even free--much worse, it's an opportunity cost. Like a cruise ship, every square inch of a theme park needs to make money (according to modern corporate views). Dagwood's iconic-to-your-great-grandpa sandwiches and a Gasoline Alley store selling "Bort's Parking Only" signs are, in a very real sense, costing UOR money if a Spongebob or OnePiece themed snack bar and store would generate more revenue. That's why I don't think you can look at the rides in isolation--they only exist as the "weenie" to get you into the land to spend on food and merch.