But Microsoft have single product. While they do sell it from 5 different department is combines to one interwoven whole.
That is great on the rise but can be terrible when every customer lost means losing network effects. The more google apps/ Libre gain traction the less valuable the windows desktop becomes. The less valuable the desktop - the server becomens less valuable and from there the DB.
Computer ecosystems are like the real stuff - they can implode with a few strokes of stupidity and bad luck but are hard to be wiped out. And microsoft have somewhat bad track record in the last few years on quality decisions. There is no future in which there does not exist sizable deployments of microsoft software.
But also metric of a company is their relevance. MS lost their ability to be trendsetters and are playing catching up.
Unless there is strong change of direction coming I think that MS will have their soviet union moment in the next few years - they will vomit a lot of territory and they will still be huge and powerful afterwards, but just not among the superpowers.