My first computer was the Commodore 64 (still have it), yes I am ancient What happened was the IBM PC being cloned and DOS being the only OS available. There were lots of other alternatives for personal computers, the Amiga for instance, but none could not compete with the clones. The fact that MS DOS was the OS was more of an coincident than anything else. The cloning of the IBM PC created an ecosystem of hardware manufactorers, and it was that ecosystem that killed off all competition, Microsoft was merely on for the ride.

I remember the first Internet Explorer. It was better than Netscape, but lacked functionality. In general Netscape sucked, slow and fluffy, it is only in recent days that Firefox has become good.

It is a long time yet before the mobile industry reach a similar state, it probably never will. The dynamics of the mobile industry will also affect the PC industry and change it drastically. This has already been going on for some time now but it will take time. This dynamic is the only reason closed systems like Apple can survive and why Android never will be the only one. The mobile industry is way to large and mobile computers are too personal, design and looks is a major factor - fashion comes into the equation.