> I think that there is a shitload of old desktop and laptop computers from 10 to 15 yrs that are still usable only with a linux distribution and that will not be true anymore.

For mainstream laptops/desktops, the 32 bit era ended around 2006 (2003, if you were smart and using Athlon 64s instead of rancid Pentium 4).

Netbooks and other really weak devices held out a few years longer, but by 2010, almost everything new on the market, and a good chunk of the second-hand market, was already 64 bits.