"After IE6 they took the team down to a skeleton crew and they stopped fixing bugs. They had horrendous security bugs and page layout bugs and DOM bugs and networking bugs. And they just said, 'Ah, the web is over. We’re going to do Windows presentation foundation,' which became Silverlight. 'We're going to do .NET. The web, that was a passing fad, sort of like television.' So…"
Now whether or not Eich is the absolute authority or not on this, I can't say, but he certainly interacted with them enough to have a deeper perspective than the average, frustrated dev in 00's.
(Source: http://devchat.tv/js-jabber/124-jsj-the-origin-of-javascript...)