"Bill is basically unimaginative and has never invented anything, which is why I think he's more comfortable now in philanthropy than technology" - Steve Jobs
Far from innovating, Gates and Microsoft have tended to follow the innovations of others. Their graphical user interface, their grasp of the World Wide Web, databases, spreadsheets, networking, browser features, tablets, smart phones - all followed behind their rivals. They lagged behind available hardware too - 64-bit Windows came years after 64-bit processors were available and being used by rival systems.
When they had the dominant market share, Microsoft allowed software to stagnate until it became intolerable. This happened with DOS v3, Internet Explorer 6, and the Windows 95/8/ME series.
This was partly due to a two (or multi)-level policy, whereby even when Microsoft did have something newer and better, instead of letting it flow through at a fair price to their wider customer base, they sold it at a premium price point to high end customers for as long as they could squeeze a "professional" price out of it, while holding the home and small office customers back with the inferior obsolescent version at the lower price which that part of the market could stand.
This happened even in the early days. DOS, the "dirty operating system", was bought as a stop-gap to secure the IBM contract, but the original idea was to replace it soon by something better, a version of Unix written in-house - Xenix. But Microsoft were slow developing Xenix, and when it was ready for the IBM PC in 1984 Microsoft continued to sell DOS to its consumer market and sold Xenix only to the corporate and academic market.
This policy was repeated with Windows NT. By 1988 Microsoft needed a replacement for the creaking Windows 3 versions, which still ran on top of DOS. So they poached a team of developers from Digital Equipment Corporation (DEC) to write one, and as a bonus the team brought some of DEC's code with them. The vastly superior replacement emerged in 1993 as Windows NT. For the first time in their eighteen years of existence Microsoft actually had a decent operating system of their own making to sell, albeit partly with code stolen from DEC. Windows NT was a heavyweight when it emerged, but at the time staggering improvements to PC hardware were taking place by the month, accompanied by astonishing price drops, and anyone could see that even cheap entry level PCs would very soon be more than capable of running NT. It was the future.
Yet instead of putting its weight behind NT, perhaps tailoring a lighter version for home use, Microsoft pitched it at the server and professional market at a high price. Astonishingly, they then set about writing Windows 95, an inferior system that still relied strongly on DOS elements, and was out-of date from the day it emerged.
Windows 95 looked modern, because it largely copied the Next and Apple Macintosh interfaces, but behind the scenes it was a can of worms. It became a standing joke for its unreliability and its "Blue Screen of Death", but was kept alive for 6 wasted years (including its continuation as Windows 98 and ME). It and Windows NT were maintained alongside each other by rival teams.
Windows NT was eventually marketed to the small user instead of Windows ME in late 2001, almost a decade after its first release, in the version called by then Windows XP.
So much for Gates driving innovation.