They are not stupid. They don't want to mess with computers. Like they don't want to mess with their cars or appliances. There is too much things to mess with and not everyone is good at messing with things and this detracts them from things they want to do in their life. So they pay a little more money and can in exchange spend more time on what they are doing better. That's called specialisation. I agree that too much specialisation is not optimal, but neither is doing many different things badly.

Great point. Bill Gates is unquestionably very intelligent but I doubt he works on his car when it is broken. Just because he doesn't work on it does not mean he doesn't know or couldn't figure out how to fix it. He has the means to have someone else do it.