Microsoft cast a shadow over the software world for almost 20 years starting in the late 80s. I can remember when it was IBM before them. I mostly ignored this shadow. I never used Microsoft software, so it only affected me indirectly—for example, in the spam I got from botnets. And because I wasn’t paying attention, I didn’t notice when the shadow disappeared.
It’s foolish to assume that Microsoft is "dead", but the gist of what the author is saying is that people are no longer scared of them… they have nothing to worry about when trying to compete. Companies like Google no doubt played a huge role in this happening.
Source: Paul Graham