johann It seems like a fair amount was planned, as the family was able to hand over quite a few things to the other maintainer...
As for Torvalds, well, it seems like the Foundation has made sure everyone was handling separate sections of the kernel and the job, and they already handle situations where he goes on vacation. I think the kernel would be fine if he were to retire; maybe not as clean without his rants and strong opinions (most of which are very founded, by experience).