Edmonton is the poster child for a failed rebuild with top picks, but for every Pittsburgh, Chicago, LA there are the following:
Florida - Warm, no state income tax, how many top picks and they are still bad
Buffalo - Hockey town, hockey market, has been rebuilding for over a decade
Carolina - Hasn't made the playoffs in 10 years with numerous top 5 and top 10 picks
Islanders - Tavares was a generational player and he couldn't consistently get them to the playoffs
Coyotes - Have been Cellar Dwellars for years
Now I know you can point to this reason or that reason as to why each team has not gotten better, but there are six examples where getting top picks year after year has not produced even playoff caliber teams, let alone one that can go on a run in said playoffs...
You could probably throw Colorado on that list too....