>let us say they ll last 4 more years
Why not 50 more years if we're just making up numbers? I still have an IBM thinkpad from 2006 in my possession with everything working. I also see people with Macbooks from the era with the light up apple logo in the wild and at DJs.
>A PI would last a lot longer.
Because you say so? OK, sure.
In your comment you didn't say Apple computers or Thinkpads. Those are different. I was talking about plain old vanilla business class laptop (because we are talking about raspberry alternative).