Besides the advice on ditching hardware on account of thermal problems is .. terrible. If you went so far as installing obscure linux distros, surely unscrewing a few screws and applying a vacuum and then some thermal paste isn't out of reach.
That was NetBSD's marketing way back in the days of "I have a Sparcstation 2 in my closet, can I do anything with it?". It really doesn't apply to the systems in the linked article, all of which ran Linux very well at the time of manufacture and for which support has been really quite well maintained.
I mean, it's no surprise really, but objectively the best system in terms of coverage for ancient junk is Linux these days. Yeah, NetBSD runs on a VAX, but does it run on a 2008 Wifi router? OpenWrt probably does!