Microkernels could use some hardware optimizations... And most of those optimizations are good for virtual machines too, so they'll get done.
In due time, message passing kernels will get so much faster than interruption based ones that we'll ask ourselves why we used monolitical kernels all this time. (And somebody will have to explain that microkernels used to be slow, and this person will be met with skepticism.)
That said, the computers we had at the 80's and 90's were completely unfit for microkernels. Mach was about the best you could have by then.
(But all that discussion about microkernels is an irrelevant sideline. Linux got adopted because it was there, if it weren't we'd probably use some version of BSD instead.)
In due time, message passing kernels will get so much faster than interruption based ones that we'll ask ourselves why we used monolitical kernels all this time. (And somebody will have to explain that microkernels used to be slow, and this person will be met with skepticism.)
That said, the computers we had at the 80's and 90's were completely unfit for microkernels. Mach was about the best you could have by then.
(But all that discussion about microkernels is an irrelevant sideline. Linux got adopted because it was there, if it weren't we'd probably use some version of BSD instead.)