I guess they will reuse for reactOS or smth but not patch it. Maybe a company who needs it would patch it. But its nonsense to patch something that noone is interested in, especially when its hard to understand the code. Microsoft tried to make its workers drunk and make them program, didn't went good. It also focuses more on money rather than readability of code.
ReactOS is still in beta development and cannot be used as a daily driver. Also, I don’t think it supports all legacy applications / games.