For all their recent challenges / failings, etc. (e.g, Smartphones / Tablets) there is one thing that can be said about Microsoft: rare is it for a firm to not only topple so many rivals (recall Netscape as but one of many examples) but to be able to do so across a wide-swath of an industry and for more than one generation is an impressive record indeed (albeit, arguably, not always having done so above board in the eyes of the DOJ amongst others).
(Source) NY Times: http://goo.gl/AWbEhN