The point of rebuilding is to get a player like Karlsson though. Toronto rebuilt to get Matthews. Teams that already have a franchise player don't typically tear it all down, they instead build around their franchise player(s). Washington didn't tear things down to the frame when it wasn't working with Ovechkin, they kept that elite piece and changed the complimentary pieces. Tbay didn't trade Stamkos when they had rough times, they found pieces to support him. The Bruins didn't trade off Marchand, Bergeron, Krejci, Chara when they missed the playoffs two years in a row, they built around those key guys.
The problem with what we are doing is that there is little hope of getting that franchise guy because we're hitting rock bottom (presumably...) in a year we don't have our own pick, and the guys we moved out to get there are young enough to be a part of a winning mix when our prospects are ready to contribute on their ELC and 2nd contracts. Everybody seems to agree that vets are needed for a rebuild or retool; in an ideal world those vets should be young enough to be part of the finished product. Karlsson, Stone, Duchene all were young enough to do so. They could easily have been the core to build around, adding Chabot, Tkachuk, White, Batherson, Brown but, have gone in a different direction. Why did they choose to go that route? Did they not have a choice (players refused to sign with them), did they feel they could be better with the return for those three (Brannstrom, Norris, Tierney, DeMelo, Balcers, Abramov, Davidsson, Lindberg, 2019 1st, 2020 1st, 2019 2nd, 2020 2nd, conditional 1st, conditional 1st or 2nd), some combination of the above?
My suspicion is that this rebuild isn't going as planned. I suspect they wanted to keep Stone and Duchene, maybe even Karlsson, but couldn't convince those guys to sign. Why they wouldn't sign probably is more complicated than just money, or just wanting to win now, but the end result is the same; a team that is forced to go down a path that probably isn't what they envisioned.