Microsoft purchased GIANT AntiSpyware in 2004 which became Windows Defender.
MS had to develop a quality AV package as it was getting a lot of reputation flak that it was not a secure OS (even though in most cases, it was users turning off security updates causing most infections).
You could apply purchasing tools to just about every bit of software e.g video players, photo editors etc.
Windows is not a closed source like IOS, and its major strength is the ability to run 3rd party packages.
If MS start buying up 3rd party tools willy nilly, they would get slated by software vendors like Adobe, Photoshop and would be rightly accused of anti competition practices (I have no idea how Apple get away with this).
My view is let MS focus on thr the OS, and 3rd parties focus on producing quality apps (MS Office probably being the major exception but that is historical).
I exclude all the corporate cash cows like Azure as that is another discussion.
Sure MS do produce basic apps for those not requiring sophistication.
In the end, MS only buy 3rd party tools if needed to maintain its reputation or, of course, to make money.
Buying an imaging tool will not enhance their revenue as there are many quality 3rd party imaging tools (free in many cases).
In fact if things went wrong, it could seriously backfire damaging their reputation.
In the end, why would MS take such a commercial risk?
