Trying to take a non cynical take: at a business level Apple's hardware business was growing while other makers were having a hard time, and I think with their current advancement in processor tech and sheer production quality, they have captured most of the market they were probably expecting to capture.

At this point, trying to expand the user base through sheer hardware improvement or trying to include fringe groups (windows dual boot users, linux user) probably has diminishing returns.

In contrast, service revenue, app revenue and accessories like air pods, the Apple Watch have a much better ROI.

What I'm coming at: they have little incentive to work hard to expand the user base, and a better ROI on expanding revenue from users of their software platform. So I'm not holding my breath on Apple actively helping for windows or linux support anytime soon.