Tanking can assure you of getting high quality picks, but a lot of things have to line up properly for it all to work.
You need to do it when the right player comes along. The term "generational talent" gets thrown around a lot these days. Sometimes it's used correctly, like with Crosby and McDavid and sometimes it doesn't, like with Bedard. You can still build around a player like Bedard, but I'm not entirely convinced that you should strip your organization completely of talent to get a player who falls short of that truly rare gift. The textbook example of this are the Oilers. In their case, they tried it with Taylor Hall, and he just wasn't the guy to empty to the cupboard for. Ryan Nugent-Hopkins is a very good hockey player, but his draft wasn't the deepest. Nail Yakupov was a disaster. Not all 1st overall picks, not even consensus #1s, are that guy.
It's one thing to shred talent, but it's another to build it back up. Sure, you can stockpile draft picks, but those picks need to be the right players with the right mix of qualities and at the right positions. You need the right people in player development. You need the right people in the AHL. You need an owner who keeps his nose out of hockey ops. You can't make mistakes there, or you wander in the wilderness.
You can't have bad luck. In 2019, the Oilers had Andrej Sekera carved out of their rebuild, due to an Achilles injury which ended his NHL career. The next season, Oscar Klefbom was forced to retire due to arthritis issues at only 26. Adam Larsson signed in Seattle the next off-season, because he couldn't bear to play hockey in the building next to the place where his father died.
Total rebuilds can work, but a lot factors (many of which are completely beyond your control) have to swing in your favour in order for it to go right.