You're wrong. Chicago didn't try to tank. I went over this before but they signed high-priced veterans in 2005 to try and make the playoffs (Khabibulin off a Cup win, Aucoin). Then, after drafting 3rd overall, they immediately traded for futures and sent them to Ottawa for 5-6 year veteran Martin Havlat (though I don't think this was a bad risk). They lost anyways and got Toews and Kane out of it.
I don't think the Hawks deliberately tanked since they made a push with some vets around 2005 (they did had to reach the new cap floor tho which could explain some signing) but the didn't just traded futures for Havlat if you consider the whole story.
In 2005-2006, Kyle Calder, Mark Bell and Tyler Arnason were the top 3 scorer in Chicago. None of them were back in 2006-2007, the year the BlackHawks had a bad season and ended up drafting Kane. The Chicago owner of the time was cheap and holded on Calder contract. They traded Mark Bell for Josh Hennessy and Tom Preissing, pieces used to aquire Havlat.
They traded Arnason for Bochenski, which they traded 1 year later for a conditional 5th and Versteeg. Traded Calder for Handzus.
That's why the aquisition of guys like Handzus(injured in 2006-2007) and Havlat had a lateral effect for the most part since they lost the same year their 3 best scorer.
And each time they realized they weren't competitive, they selled some good vets instead of selling more future in an attempt to make the playoff. The year Hawks drafted Toews, they traded Jaroslav Spacek in January who was a top pair defenseman for them for rights to a prospect. At the trade deadline of 2006-2007, they traded Brian Smolinski who was among their best scorer for a pick.
The Habs don't need to deliberately tank anyway, a high pick is secure for this season, they just have to think long term and not trade valuable young assets or sign UFA to boat anchor contract like Hoffman or Savard , sell some vets and another high pick in 2022-2023 will be a side-effect of all this. This team isn't turning into a playoff contender as soon as next season. Hopefully we can get as lucky as the Hawks and fall back to back on two game changing talent.