not everything needs to be connected to the internet. it's nice to have an old simple system that is secure because it's connected to nothing. it's solid, reliable and doesn't need megabytes or gigabyte of updates to keep secure.
solid hardware built to last. this is selection bias at it's best mind as the ones we collect are the ones that have survived and not the flimsy cheap systems that died early. problems that do exist have been rectified or worked around so there should be no nasty shocks in the next 10 years with them.
single tasking. it allows us to focus on doing one thing and doing it well. we've grown too used to having 10-20 programs running at same time and swapping between them. it can be beneficial to concentrate on just one thing avoid distractions.
You’ve clearly not owned Atari gear :-). The keyboard eventually goes. I think I’m on #3 for my Atari 1200. I never owned an ST so I cannot speak to the durability of those devices.
as a fan of sinclair i know about bad keyboards :-) but they could be repaired. there was a thriving market in add on real keyboards. looking today and i can find
https://blog.adafruit.com/2023/06/14/a-zx81-replacement-mech.../
which for a system over 40 years old is not too shabby.
it's not like some modern machines where if the keyboard was broken by someone eating toast nearby the machine can only be fixed by the manufacturer for considerable cost.