All those teams were bottom feeders for 20 or 30 years and finally got the tank right the last time they tried it after 20 or 30 years. You can't just look at the last time they tanked and it worked in isolation. They tried tanking many times over 20 or 30 years and failed each time.
But, I am curious what teams do you think "tanked" and it worked to the point where they became an elite team? I guess you can say Washington, but we'll see if they can sustain it past this year. The Texans? They seem to be stuck at mid. Buffalo? It took 17 years of losing before they got Allen.