The amount of early 2000's forums I can tell a similar story about is incredible ... companies willingly just jettisoning their audience.
It's either killing off forums completely, or "upgrading" to the point of being unrecognisable, or requiring everyone to make a new account and ... I can't even be bothered to write it.
Old-school corporation-run internet forums being killed off in the 2010s was usually due to costs of moderation (IMDB, Amazon) or brand-protection reasons (Lonely Planet) or both.
At the time, I was angry at this as a user. But looking back, the forums would have declined anyway. With most people today using the internet from their phones, and younger generations chiefly interested in video, there just isn't the same societal support for thoughtful long-form text typed from a computer keyboard. The surviving independent forums I'm on are greying out at best, or have shrunk to a few cantankerous or dotty people at worse.
One day without warning, they deleted it.
Complete contempt for writers who were frankly far superior to any on staff. I was just a lurker, I've no personal investment beyond that.
I can't remember the last time since that that I visited the site with intent, the arrogant, contemptuous destruction of brilliant writing - that's its legacy for me.