Re: Macs typically have a longer usable life than Windows PCs ...
I can vouch for that. I have one from 2010 still going strong (headless server) and 2 from 2012 editions - again running one of them as headless server and the other as my working from home kit.
2010 isn't anything of a big deal. Still over half of the PCs at work are on an upgrade cycle, because they pre-date 2010.
I've worked with other customers who still have PCs from the turn of the century in production environments. They still wobble along and don't cause any problems. They are generally attached to plant that costs high six figures.