Microsoft turned down an offer to bid on Red Hat, whose enterprise focus is a much better fit for them, before the sale to IBM so there's no reason to believe they would bid for Canonical.
Wow. That sounds surprisingly probable, now that you bring it up. Ubuntu is wildly popular, but requires a lot of money. Microsoft has a lot of money and seems to be trending toward open source.
https://www.businessinsider.com/red-hat-deal-talks-with-amaz...