Pfffffffffft I have no sympathy whatsoever for the Sens, they had more than adequate resources, Dorion is proving he's just not that good. DeBrincat is more than likely just tired of being in a losing situation than he is wanting to go to a bigger market.
Word to the wise, never, ever publicly state that "the rebuild is over." Just send the damned team out there and let expectations fall where they may.
The NBA thing is overstated as well, didn't stop the Milwaukee Bucks from winning a title, and if the Nuggets don't make it, that won't be the reason either. It's annoying that the Lakers can seemingly buy their way out of trouble every few years but they're also paying the price for their hubris.
Small markets always sort of suffer and it is worse when you have a soon-to-be UFA wanting to decide where he wants to go, which majority of the time is a major market. The same thing happened to Columbus as well and that is the price you pay for risking this type of stuff. I think Dorion knew that DeBrincat was never going to sign in Ottawa, but still traded for him to potentially showcase that his team is on the upward trajectory with another fellow USAer as Captain.
In terms of the NBA, I think what happens is if a team gets a franchise player, then that club will have superteam potential as the Bucks did in drafting Giannis, Curry with GS, or Toronto did with Leonard. The problem is that a lot of these players move when their deal eventually runs out and become mercenaries. Nets are a perfect example of that, LeBron going to LA is another example, and Anthony Davis asking for a trade out of New Orleans further showcases what I mean. There are a lot of dead franchises in the NBA IMO like NOLA, Charlotte, Atlanta, Washington, Orlando, Detroit, and Utah which reminds me a lot of Ottawa (Utah). Always have good players, but nobody wants to stay there. Minny was a dead franchise for the longest time too, but supposedly got a franchise player and I would not be surprised if they're the next superteam UFAs will want to jump to.