[mrozbarry]

I think it's because QBasic was, among many things, a bit of a bridging language.

- Basic had existed even before displays and keyboards were popular, so many software developers from that era could appreciate it.

- Microsoft included QBasic 1.1 for free with some of their operating systems.

- All things considered, it was fairly compatible (depending on what the code did) with GWBasic and even basic/basica from old IBM terminals.

- The language was also easy to understand which made it ideal for education

Probably among other points, this brought a pretty large and diverse group of people who loved programming together.