This is where the discussion goes awry because, unlike the discussion of DAS where
@lentesta has provided specific data to show DAS use, we on this thread don't have such information for the other parks. I'm sure there are people on social media who use DAS at Disney and then don't elsewhere - not debating that exists. But a significant percentage of DAS users doing that? There's no
data to make that claim.
Anecdotally -we've gone to other theme parks, and yep we use their disability services while there. One of them I would argue has a much more generous program than DAS - you get to enter at the exit, and you can stay on the ride for 2 consecutive rides without getting off if you so choose. It's a theme park designed for kids - mostly younger kids - but even during the summer, it's clearly not abused (and also no documentation required there).
A six flags, though, and universal Hollywood - we definitely won't return to the latter for some time, and aren't likely to seek out the former. In both instances because the rides aren't super accessible. We go to Disney because the rides - even many of the thrill rides - are so much more accessible. I would posit that the accessibility of the rides (or lack thereof) at places like 6 flags drives down the numbers of those with disabilities going more so than their documentation program. Having just done universal's documentstion process, to be very frank, it feels like theatre.