MS stock is at a 14 year high right now. Big gain today.
Exactly. This is the primary reason firings of this magnitude occur. The secondary reason is akin to why a new coach or general manager of a sports franchise cleans house and restructures things when they come in...they want to do things which, at least on paper, make it appear that the organization is being run better than when the last guy was in charge.
So, yeah, basically firing 12 thousand people makes share prices go up for awhile, helps some large scale investors make a quick extra few mil short-selling, makes Wall Street happy because cost of labor is their number one enemy, and at least for awhile makes it look like Satya is going to do "real things" to better justify his bloated salary than did Ballmer.
Business itself is a game, people.