Dan Reisinger found 10 things tablet PCs cannot do. He is right of course, but that does not matter. Everyone does not need to do everything with their PC. Tablets have a place in the world where smaller, cheaper, more portable matter more than feature-bloat. Conversely, there are some things a desktop PC cannot do like be portable. Notebooks are portable but they are bulkier and heavier than tablets so those who love portability will choose one or the other.
Every kind of personal computing device has a role otherwise they would not have been created. GNU/Linux has a role in personal computing as well. Perhaps GNU/Linux cannot run some application or other but it does not matter. Many will be quite happy with what they get from GNU/Linux, flexibility, reliability, performance, and low price. I don’t run any app that will not run on GNU/Linux and I do a lot with personal computers. I only know a few people who need some particular app that is not available on GNU/Linux.
Even my wife has been converted. In two weeks we have found only two features that she had with that other OS that she does not have with GNU/Linux and we have simple work-arounds for both: download a file and work on it on the PC or run some particular client app. One feature was an ActiveX thingy on a particular website. Fortunately she can download a PDF and use it in GNU/Linux. The other feature was working transparently with a Nikon camera (PTP only). She has to run a client application to transfer the pictures. That was not noticed for a week because she was using a Fuji camera for the first week. She does all the usual things in a similar manner and can open all her old files. So, she has the same capabilities as before even if they are accessed differently. She does have a system that will not slow down however. GNU/Linux works for her and our grand daughter who is just learning to click a mouse.