EDM is doing well this year, but have had years of futility and high draft choices. Getting a McDavid, or even a Draisaitl is extremely rare. TOR has also had years of the same. Then you have teams like BUF, ARI, OTT, CBJ, NJD. Year after year of high draft choices, and are still struggling to make the playoffs let alone contend for a Cup. It looks like DET might finally make the playoffs this year, again after years of futility. We'll see about CHI.
Bottom line is that tanking for high draft picks is no guarantee of future success. I think it's more strategic tanking, holding onto draft picks, competence, and luck(Aho 35th, Pastrnak 25th, Kucherov 58th, Point 79th, etc) that determines how successful a team is.