imho. you have to look at those statements from the eyes of the early 1990ties: back then it was clear, that microkernels are the future*) ... but: just not yet ;))
why? because cpus in microcomputers where still pretty slow and the performance-penalty for using a "full blown" microkernel a la [cmu|gnu] mach was not justifiable ... again: at least at this point in time.
which imho. had 3 outcomes during the 90ties etc.:
1. the development of more lightweight microkernels - idk. for example L4 from i think the technical university of dresden/germany is the first which comes to my mind
2. the development of "hybrids" to mitigate the performance-penalty - a la darwin/the base of mac os x: a combination of cmu mach and freebsd hardware-support ... why the older cmu mach? to avoid the GNU licence ;)
3. the persistence of somewhat modularized monolithic kernels a la linux (and *BSD)
*) afaik even early versions of windows nt, which was developed during that time, tried to incorporate some aspects of microkernels, which where removed over later generations :))
