[pjmlp]

There are many reasons, none of them was quality.

1 - Mismanagement from Atari, Commodore and others

2 - Microsoft deals with OEMs

3 - Pretty cheap Taiwan and Chinese parts, some of them with doubtful quality

4 - Windows piracy, alongside the cheap parts, allowed many small PC shops to thrive and offer nicer deals

5 - PCs were the majority of computers at work and school, so the only one parents saw as a good buy for their children future.