That they were good at the time doesn't mean that they didn't start bleeding their best talent as the ownership and management factors impacted the on-ice product. The Peca holdout and eventual trade did not work out for the team both in terms of the personnel received and the factor on Hasek's departure. Hasek's departure was the next, where they were backed into a corner and got pennies on the dollar. That's the sort of talent bleed I was talking about -- they deal good players over multiple regimes and haven't recouped the value well, be it who they got or who they picked. Toss in their struggles at the draft table to find, draft, and then sign talent that could one day help them on the ice. The cycles of their struggles seem to coincide at least anecdotally with draft shortfalls 6-8 years prior. Even now, there aren't any 26-28 year olds on this team (even if they had survived the tank) because the early 2010 drafts failed to deliver value.
Their drafting actually wasn't horrendous those few years. From 2008-2013 they drafted Myers, Ennis, Kassian, McNabb, Foligno, Pysyk, Armia, Girgensons, McCabe, Risto, Zadorov, Compher, and Petersen. 2 NHL players per draft isn't in the disgustingly bad box. It's sort of bare minimum of what you need to survive. But the problem is, as you alluded, when you're just a healthy mediocre, you have such a razor thin margin of error. Myers, Kassian, McNabb, Pysyk, Armia, Zadorov, and Compher were all pissed away as assets one way or another. Others like McCabe and Girgensons may have panned out, but saw their development massively stall when they go to the pros. Ennis is probably the asset we did the best on, in terms of him being a top 6 forward here and netting us what looked like a decent return in trade, but even that is looking sucktastic now. Le sigh.
