Because the cost of entry is remarkably high. And currently everyone except Ron desantis thinks the company currently providing the service is doing just fine so they aren’t shopping around for a new provider, making it even more difficult for a new provider to be successful.
If these ‘fraught studies’ being taught as AP classes are really so fraught then colleges won’t offer credit for them and then no one will take the classes. Or perhaps if they are so fraught but credit IS offered then maybe college professors will use them as a jumping off point for discussion of contrast with different perspectives. Which is kind of one of the main educational goals of college even though Ivy League educated Ron Desantis would never admit it.