Microsoft is 15 times more valuable than Sony is.
Microsoft has enough cash reserves alone to outright buy Sony twice; and that's after Sony's value soared following this announcement.
Of course Microsoft are far bigger, but that doesn't really mean a whole lot in this context.
Even if Microsoft
wanted to buy Sony (which would make no sense), Sony would have to want to sell. There are other ways to acquire a company, of course, but let's just keep it simple. Let's assume Microsoft convinced Sony to sell. How do you think the market is going to react to that kind of takeover or purchase? Especially in Asia where a lot of Sony's value lies and Microsoft have less brand loyalty? Speaking of brand loyalty, it seems to me Sony are a company that have a higher than average brand loyalty among their consumers. I can't imagine people would be pleased. What about the incredibly valuable PlayStation brand? I imagine the reaction of a lot of consumers in the console gaming space would be catastrophically bad. So suddenly Microsoft would be left with a shiny new asset they probably had to overpay for that is now severely tanked in value. You can see why these things start to make little sense when we start digging into them. Microsoft are too smart for this. These days they are a vibrant and healthy company. They aren't in the business of lighting mountains of cash on fire (tens of billions in this case) just to please Xbox fanboys. The idea that Microsoft could just buy Sony "if they chose to" has always been largely nonsense. It is one of those things that is "technically true", but quickly falls apart upon further inspection. Hey, it is technically true that Scarlett Johansson has never turned me down for a date, but somehow I think my chances remain slim even if I was somehow able to ask her out.
I like it just the way it is. A healthy and dynamic Sony and Microsoft that continue their healthy rivalry while pushing each other to innovate and find new ways to appeal to consumers. It's a win/win for us.