First: A stock can rise for reasons having zero to do with the reality of the business behind the stock, for example mispricing, availability or the lack thereof of alternative investments, inflation, currency devaluation etc. Second: To me it always leaves a very foul aftertaste when the achievements of a team are ascribed to whoever the visible front-person is. I find it hard to believe that among the other 149999…
Bill Gates built an amazing airplane. Steve Ballmer crashed it in the desert. Satya Nadella rallied the survivors, put it back together, and got it flying again. Yes, he absolutely deserves the credit just as Ballmer absolutely deserves the blame.
He was not, however, a product guy. Witness their failures with the Zune, mobile, early cloud computing. His problem was that he always tried to do what would be best for Microsoft and not the customer. You can get away with this if you already have an install base (windows/office), but with net new products people will look at what's best for them first. Even with developers developers developers he tried too hard to get people to use pure MS tech and made developing for the web on MS ugly if you using anything other than .NET. The result is a generation of developers on Macs and to a lesser extent linux.
Funny enough, thinking of the customer is what MS did with the xbox and it worked out well enough.