Arch was young in those days but I think fairly well known? we were quite vocal, opinionated and interjecting our views everywhere by the time of the Xfree86/Xorg switch. Perhaps it is just my view from being a part of it but I remember encountering the Arch reputation everywhere I went. Or maybe it is just the nostalgia influencing me.
Could be. I don't remember Arch being on my radar at that point though. But it wasn't long after I switched from Gentoo to Arch (and then Debian for a decade due to lack of stability before going back to Arch 7 years ago or so).
A few years before the Xorg thing there was also the 2.4 to 2.6 kernel switchover. I think I maybe was using Slackware at that point, and I remember building my own kernel to try out the new shiny thing. You also had to update some userspace packages if I remember correctly: things like modprobe/insmod at the very least.
2.6 was also the switch from OSS to Alsa, which caused some fun, Alsa really was not ready for prime time.
Oh yeah, you just unlocked a forgotten memory. I was actually lucky there, I had a SoundBlaster Live 5.1 which worked just fine on ALSA (hardware mixing even worked out of the box). But I remember lots of other people complaining on IRC about it.