[alkonaut]

I think the first reason people don't care for installing e.g. Thunderbird is that they check mail on a) mobile, b) work (which is usually outlook, or at least mandated by someone else).

If I asked 100 friends "did you use email today" 99 would say yes. If I said "did you do it on a computer" then 50 would say yes (those that work at an office). If I said "was it your own computer" then maybe 1 would say yes.

I think for us that sit at our own computers regularly, it's hard to imagine just how extremely rare it is for people to actually use desktop/laptops for personal use these days.