In the abstract, I think the "plan" for rebuilding teams is trending towards short rebuilds rather than multi-year rebuilds. Edmonton, Buffalo, and Arizona have to give organizations pause when considering a rebuild where the team intends to be bad for 3ish years, stockpile assets and then come out of the basement. It can be successful, but it also is not a guarantee of success. I think we'll see teams doing what the Rangers seem to be doing where they sell a bunch of older/rental assets in a throwaway year, get multiple 1st round picks (including an early one), bring in a couple younger guys as part of those trades and then attempt to add in UFA over the summer. Or a retool like we've seen with the Blues where you remain in playoff contention but sell for futures at the deadline.
With the league trending younger, I think that 3+ years in the gutter is more a sign of bad management than a successful planned rebuild.