Basic EEE strategy (embrace, extend, extinguish). For example, take XMPP. It was a wonderful federated chat protocol. Google joined it with its Google Talk application. All was well. Until it wasn't. You see, Google added some "new features" that could be used only with the Google talk app and account. So people flocked to it. All is still well. But then google decides to close the gates - Google Talk is its own thing now and you can't talk to people on other servers or with other apps. Take what hapoened wit XMPP. Google embraces XMPP with Giogle Talk. Google add some shiny "new features" that are exclusive to Google Talk (extend). Google cuts off XMPP access to other domains other than the Google Talk domain, thus finishing the extinguish phase.

Just replace Google with Meta/Facebook/Zuckerberg, Google Talk with Threads and XMPP with ActivityPub/Mastodon/Lemmy and you can see how it could happen. The XMPP Wikipedia page has it covered very well, and there's a dedicated Embrace, extend, extinguish page on Wikipedia if you want to read more.