The DOJ had MS on the ropes in 2000 until Bush fils became president and in the words of one journalist "snatched defeat from the jaws of victory" and walked away from the case.
Sadly, an Antitrust case against Microsoft (under Nadella's crapware reign) is less likely to happen while the DOJ is busy with Apple.
While I agree that Microsoft's treatment of Windows is basically criminally negligent at this point, it's a lot harder to prove damages with them than it is with Apple right now. I also suspect that any prosecution against desktop OS service bundling would end up lumping Apple in as well anyways. One step at a time, eh?