According to CNET the problem with Windows 8 is not whether it is a good or bad operating system. The problem is Windows 8 is in a dying market. Dell made some really bleak predictions in its latest SEC filing stating that the PC business was deteriorating.
Business Insider points out that as the tablet business explodes, the netbook business is shrinking badly, and they have the graphs to prove it. And things will likely only get worse. Right now, tablets and phones are mainly consumption devices. But as their software improves, expect them to be start eating into the word processing and spreadsheet business. This can't be good news for Microsoft.
But don't count Microsoft out yet. They still have the time and money to get into the game. However, it would seem likely that some PC manufacturers will next survive the next 5 years.