And even so, how can you say it works 99% of the time if you have to go and research each piece of peripheral that you want to use? Normal users go to bestbuy or amazon or whatnot and buy a microphone, they don't want to go and see if it works on ubuntu or whatnot or have weird behaviours at home. you can blame manufacturs for not supporting linux while they support win/mac, but again, normal users experience just isn't that great.
You said you are running linux for you and your relatives. Who installed it on your relatives machines? Who checked the compatibility of each hardware and maybe even bought some replacement things to work on linux? I know most users/relative I know wouldn't go to websites to try to find out if this or that works well with this and that. They just want to go to a shop, buy a laptop+accessories and plug them in when they get home