I don't think any other studio library would have had the emotional impact of Disneyland. With all due respect, if you actually believe WB could have created a park with any of the actual heart and warmth that earned DL its huge fanbase over the decades using Bugs Bunny and crew.... Sorry. No. It could be a nice park, sure. But it wouldn't have anywhere near the impact of a park based on beloved films like Snow White, Dumbo, Alice in Wonderland, Sleeping Beauty etc. and the Americana and True-Life documentaries coming from Disney.
We'd never know what we were missing, just as if the Beatles had never formed we'd have still had great music in the 60's and 70's, but
there'd be no Beatles phenomenon and influence. There'd be something else in its place, but it would be different.
I've been to alternate Earths! I know what I'm talking about! Howdy Doody Land was interesting, but it was no Disneyland!