I'm not sure there's much more Microsoft can do to improve Windows – those areas where they've swung and missed are normally due to their complete lack of an ecosystem. Since Microsoft completely blew it with mobile, Windows is left with a glaring hole in its product offering. Could you imagine if it had full Continuity, Handoff and messaging features etc like Apple? It would make leaving the iOS/macOS ecosystem immeasurably easier.both Windows and macOS are mature operating systems, what sort of features would you say that MS or google would need to add to leap frog apple? I will say that MS has swung for the fences a number of times with its updates, sometimes providing nice updates, sometimes swinging and missing. Apple hasn't really done much, Mojave's biggest feature seems to be dark mode.
As it is, Apple is able to effectively take the foot off the gas with Mojave as they have already created the ecosystem that is not only completely holistic but also almost impossible to give up, even when the hardware is lacking. All PC manufacturers can do is throw every bell and whistle into hardware as the software can never match up; at best, it's a fragmented marriage with Android that sorely lacks Apple's finesse and polish.
That's not to say Apple isn't completely resting on its laurels to some degree but, in their defence, the ecosystem didn't happen in a vacuum. Apple fought hard to create it and now has the benefit of being able to simply print money because of it (also having a heads-up over the competition with selling cross-device services).