Mainly because, "well-supported hardware", could change at any time. It felt better to me to attempt a clean break.
On top of that, I've actually had to spend far less time computer janitoring it than I have on the various *NIX installs I've run in those same 6 years.
I totally understand not wanting any OS-based surprises while trying to get work done, but as long as your CPU and motherboard are supported, you're generally good to go.