There is no guarantee as far as even a generational talent goes. You're losing for, an at best, 15 or so percent chance of winning the draft lottery. Imagine Colorado fans reaction to getting the 4th overall pick this year.
That and the media coverage for trading fan favorites can be brutal.
No movement clauses for players that are key to a winning teams success are way more common too.
Most ownership groups are looking for maximum return, and generally selling off star players hurts the bottom line.
"League Parity". Thanks Bettman.
No matter how bad you think you are, there will always be a team that will plummet due to injuries, off ice issues or what ever else you can shake a stick at.
Unless you're ahead of the game and know a bad season is on the horizon, a total teardown is almost impossible. We moved Hansen and Burrows, but can you imagine the logistics in moving both Sedins, Edler, Miller and possible guys like Tanev, Sutter, Sbisa and even Markstrom. Yeah, not happening often. Remember the pre-Ovechkin teardown? That would be impossible in the cap world.