There's an interesting pattern with the two most successful tanks of the last 25 years (Hawks and Penguins).
Both got a least one superstar with a high, but not first overall pick (Malkin 2nd overall, Toews 3rd overall)
Both had a superstar go first overall (Crosby, Kane), though obviously Crosby is in a class of his own
Both had a superstar draft pick after the first round (Letang 2nd round, Keith 2nd round)
Both had multiple good players get drafted outside the top 10 as well (Seabrook/Crawford/Byfuglien/Brouwer/Bickell/Hjallmarsson and Whitney/Talbot/Goligoski)
Pittsburgh has the higher highs in drafting, and obviously Fleury and Staal are outliers in this regard.
But both teams combined superstars at #1 with 5+ good picks elsewhere.
Getting three superstars in the draft (Crosby,Malkin,Letang Keith/Toews/Kane) in a few years is a huge get. Filling the team with other great picks goes a long way too. Both teams had to retool significantly after their first Cup, but the depth charts from strong drafting helped a lot.
Speaking for Hawks, they had a great foundation in place prior to Toews/Kane being drafted. The issue there is most people have no clue what other team's prospect pools look like outside of the high-profile names, and even if they follow the rankings and such, noobdy has any idea how all those players turn out until looking in hindsight much later.
Hawks would have had (age they turned in 2006 calendar year in parentheses) in the system, whether NHL roster, AHL roster, draft pick not yet officially in the org yet:
Duncan Keith (23)
Brent Seabrook (21)
Niklas Hjalmarsson (19)
Patrick Sharp (25)
Corey Crawford (22)
Dustin Byfugilien (21)
Tuomu Ruutu (23)
Troy Brouwer (19)
Dave Bolland (20)
Bryan Bickell (20)
James Wisniewski (22)
Cam Barker (20)
Adam Burish (23)
Jack Skille (19)
Brandon Bochenski (24)
So even though the Hawks didn't really add anything besides Toews and Kane from the 2006, 2007 and 2008 Drafts despite missing playoffs all three of those years, there was already a great foundation in place.
Yet during the 2005-06 season, nobody would have really looked at the Hawks as a team that had such a good foundation where they just needed a couple homerun top of the draft picks and could leverage that to a mini-dynasty. Many of those were lower round draft picks. Someone like Patrick Sharp would have been viewed as old and likely tapped out with his half ppg amidst more opportunity after being traded by Flyers. Of course there is no way to account for a Bochenski for Versteeg (turned 20 in 2006 calendar year) trade steal and then they also traded Ruutu for Ladd (turned 21 in 2006 calendar year) to give a couple more guys on the timeline.
The narrative circa then would have been the Hawks have been trying and failing to rebuild for a while with lots of busts, terrible ownership, a team nobody including the former hall of famers wants anything to do with. The highest ceiling players amongst the list above would have likely been considered Cam Barker and Jack Skille.
This is what make rebuilds so tricky to properly assess. Had more of those guys gone in a different direction post 2005-06, we're looking at a scenario where Kane and Toews step into a void roster with maybe some young guys that have future NHL journeymen potential. They're asked to carry a big load with little to no support behind them. As the rest of 2006-2008 drafts don't bear much results, they have to resort to more desperate free agents singings to try and get a core, but of course nobody with good options wants to play there. Maybe six years in, both are looking to play elsewhere by then.
You just don't really know what teams have going on in the system until you can zoom out and look years later and say "oh yeah, their prospect group was really stacked then".