It's not happening ever period.MS buying Square would be devastating to Sony. They can never ever ever afford to let that happen. Also MS buying SE is kinda stupid as well since their games don't do all that great on Xbox consoles.
Reasons as follows.
1. The company would have to be open to being bought.
2. They sell maybe a 1/10 alone on how much Playstation or Nintendo sells. Why sell to someone who can't turn a positive profit for the company.
3. Japan is a country open to 'trade" not ownership.
4. Microsoft turned their whole recent acquisition into a America vs Japan situation which is one of the worst things they could have done in that situation.