What definition of tanking are we using? Teams and coaches never tank. Front offices might recognize that they're not going anywhere and need to stock up on picks and prospects for a few years to be better in the long run. Is that tanking? Teams like Colorado, Buffalo, Edmonton (finally), Carolina have been bad for years, purposely stocking up on picks and prospects, and are now reaping the benefits. Tampa Bay is reaping the benefits of "tanking" or being bad.
It may not happen instantly with one draft, or possibly even two. But there's a reason teams focus so much on building through the draft, and there's a reason that when teams are past their expiration date they start selling off veterans to get picks and prospects.