Most distros were stable well before Arch because Arch worked out most of the bugs for them and documented them on their wiki. Arch and other bleeding edge distros are still a big part of the stability of linux even if they don't break all that often anymore, they find a lot of the edge cases before they are issue for the big distros. In 2005 it was not difficult to have a stable linux install, you may have had to hunt a bit for the right hardware and it may have taken awhile to get things working but once things were working they tended to be stable. I can only think of one time Slackware broke things for me since I started using it around 2005, it taking on PulseAudio caused me some headaches but I use Slackware for audio work and am not their target so this is to be expected. Crux was rock solid for me into the 10s, nearly a decade of use and not even a hiccup.