It was also more convenient to have Internet Explorer ship with Windows.

But it happened to be part of MS strategy to sideline other browsers, and gain enough power to become the de-facto standard. We got lucky and avoided that, but doing only what's most convenient at any given point in time can be harmful over the longer term. After all, Microsoft at that time tried to established their (patent-covered, binary-blob) .doc as the format for the web, instead of the open HTML.