If the Sharks went full rebuild, it would take anywhere from 5-10 years.
This is because they aren't going to get anywhere near full value from dealing whoever in their current core would be willing to go. The trade clauses are too restrictive.
Look at the Senators, they are already pretty much three years into a rebuild and they are still a bottom feeder. It's a similar scenario, but I doubt the Sharks will get as much for their core as the Senators did, and that's even with the mis-steps the Senators made along the way.
The only way I can see the Sharks pulling off a rebuild would be clearing the deck by getting the best offers for Karlsson, Burns, Couture, Vlasic, Kane, etc (which will all be soft offers because of NTC issues), and then loading up with assets through taking on bad money/finishing low enough in the draft to get top end talent.
There could be an argument made that Kane/Karlsson/Couture are young enough to keep around for a 5 year rebuild. That the Sharks could try to move on from the other older core players and keep those three along with Lebanc, Hertl, and Meier. But that would be contingent on those players wanting to stay through a rebuild. The Sharks obviously wouldn't have to trade them, but teams rarely like keeping players around who don't agree with the organizational goal. There would also be the downside that the Sharks probably end up in that middle ground where they aren't bad enough to get a good shot at top end talent, but aren't good enough to be a contender or consistently make the playoffs. At that point, that's more of a re-tool than a rebuild.
I think it's important to make a distinction here between "value".
So, first and foremost, there's "market value", which is what another team would be willing to pay. I totally agree with you that the Sharks probably wouldn't get full market value for guys like Burns because the trade protection limits his value.
However, there's also "intrinsic value", which is a totally different thing. There's a solid argument to be made that intrinsic value on Burns' contract has been a negative thus far, and it is almost certainly going to be a negative going forward. Just trading Burns for absolutely nothing is trading him for far more than he is worth, in terms of intrinsic value.
I'm using Burns as an example because he's kind of in between both ends of the spectrum in that he probably does have positive market value around the league, but he also legitimately sucks this season and probably won't play up to his contract going forward. But, based on what we hear from GMs, coaches, and players around the league, as well as Norris voters I'm almost certain that his market value right now is still pretty high. Even if the Sharks can't get full market value for Burns due to his restrictive clause, they will almost certainly get something that blows his intrinsic value out of the water.
However, most of everything I just said here applies to all of the big contract guys to some varying degree. I think that the intrinsic value on every single one of the Vlasic, Couture, Karlsson, Kane, and Jones contracts is negative, given how those players have performed this season and given how NHL players naturally age. So, if you trade them all right now, you might get significantly less than market value due to the restrictive trade clauses. But, just by removing these contracts from the organization, even if you get nothing return, I think you improve the intrinsic value of the assets in the organization. And again, I think that market value for these guys is so screwed up that even after it their market values are slashed by their trade clauses, it is still going to be so much higher than their intrinsic value.
There's an argument to be made that one or two of these specific contracts will have mild positive intrinsic value going forward, especially if the team can rebound and become a contender again by years 3-4 of Karlsson's deal, but as a whole, I don't think you can make an honest, unbiased argument that those 5 contracts as a whole will have positive intrinsic value. I mean, going forward at the start of the 2020-2021 season, you will be paying $253.5M for:
- 7 years of Erik Karlsson
- 5 years of Evander Kane
- 5 years of Brent Burns
- 7 years of Logan Couture
- 6 years of Marc-Edouard Vlasic
There is no chance in hell that you are getting your money's worth out of that group of 5 as a whole.