The curious thing is that Reddit is as valuable as it is because of what it gets from its users (free moderation, free user-submitted content.) There's always been a sort of implicit agreement that it's a symbiotic relationship -- reddit provides the house/utilities, users provide the stuff, and mods do the clean up. Third-party devs were an extension of that -- making it easier to connect the parties.
Yeah but that symbiosis community stuff is for when you're still growing. Once you're big, it's time to pull up that ladder, put on the corporate mask, and start cranking that ad revenue at all costs. You've got a million rubes doomscrolling past your homogenous r/funny - i mean, r/all - slurry who don't know the difference between an ad and a real post. People who care about things like UX and quality posts are a minority who you are free to exploit for as long as you're useful, and then crush once you're done with them.
I seriously think this is just reddit finally thinking "yup - we've won - time to start acting with impunity for anything that cuts costs (like not maintaining a public API) or increases even the smallest bit of revenue (like managing to convert 1% of apollo users to first-party-app users while alienating (no pun intended) the rest).