Strange to bring up Master Chief when the downfall of trad PC gaming that you miss began with xbros.
It seems stronger than ever to me, and I started in 1993. Consoles are becoming more PC like. PCs can now be more console like, if one so desires. In many ways we get the best of all worlds.
Halo is often seen as the beginning of the end for these types of games. I'm just happy I was born early enough to have caught this previous era, if Halo had been the game of my youth with no options for tinkering or self expression my life might look a lot different.
Early Id games had only the smallest modding capacity built-in (loading mostly), with the community stepping up with original tooling. There were also fewer games to play, which concentrated community efforts. Games were simpler too, which also made modding easier.
It was also daunting to make ones own game from scratch. Around 2000 friends and I failed repeatedly going down that path. (While the mods we made were mostly released.) Today it's so much easier to make games and even mod those based on common engines.
Dedicated servers are a loss yet they often had rampant cheating. They were also painful to setup and maintain compared to private party systems from the game creators. Hopefully with some tweaks to the law, they can be incentivized to open source their servers or at least keep them alive.