It's not about the money, though. If it was, they would have just said "third-party API access now requires Reddit Gold", and a bunch of us would still have stayed there, giving them more money (and content) than they are making now.
Instead, it's about fundamentally remaking the site to actively drive conversations toward things people pay to hype, and not have those conversations spring up organically. Steering traffic is much harder to do when it can be accessed through third parties.
They don't want users creating content around what interests them. They want to charge users to interact with content that advertisers pay to host.
I was a very heavy Apollo user. I was ALREADY paying monthly for it and if Reddit would have released a reasonable API charge structure and worked with devs, I’d have been happy to pay more for it because I used it every day.
They shot themselves in the foot trying to create a walled garden, now it’s just bots complementing each other in weirdly verbose comments back and forth.
That, and Reddit was being used to train AI. They saw that and decided they should shut off the API unless companies paid, and the hell with all the users harmed by the change.
It's funny that you say they're driving conversations. Whenever I end up on Reddit because of a search I notice that only the top level comments and very rarely first responses to them are visible.