Yes. What they specifically did though was extend the protocol so that anyone who wasn't using their version of XMPP via Google Talk would be incompatible or seem "broken" when it really wasn't. It's just that they were using non-standard features, both incentivizing people to just switch to Google Talk and for development on the core protocol to slow down.

I bet money Threads is going to do the same thing. They'll introduce Threads only features that don't work with all the standard Activitypub implementations, causing frustration with Thread users and putting pressure on people to just jump ship to Threads from standard Activitypub implementations.