It’s entirely plausible that this is the case for your wife’s family and others, but it’s hard for me to imagine a household without at least one non mobile computer. However, I can.
Without non mobile internet, though? Again, I can imagine it … But it seems wrong.
It shouldn’t be so hard; I was around before the internet was prevalent. My life now involves constant internet access, though, so I guess it’s weird to me that some people have lives that don’t - and especially that that might be the average.
One must always remember the words of George Carlin, I suppose.