That's naive.
Dorion is human, and as a human, he knew that the team was going to have new ownership and it was important for his job security to have a big season. It'd be more difficult to make a change at GM if the team made, or almost made the playoffs. Despite what we say on this board, he's not an idiot.
Heck, anyone who watched "Welcome to Wrexham" would know this. In the show, after they closed on the purchase of the team (with only part of the season left), it was brought to the attention of Ryan Reynolds (our future owner) and Rob McElhenney that there were concerns/rumors amongst the players and coaches about the change and their job security. Their answer? "Go out and win. If you win, it'll be hard to make changes to a winning team. Why would you?"
That's how it works. So Dorion very well knew he had to win.
In Wrexham, the team didn't win. So there were big changes the second the season ended.
Debrincat was an acquisition to help that push this year. The hope was that being part of an ascendant, winning team would convince him to stay. But there likely was no long-term plan beyond that. How could there have been? Debrincat said himself that no one from the Senators talked to him or his agent prior to the trade. It's hard to have a "solid framework" when the guy who actually needs to make the decision is not involved in putting together that framework.
Maybe it turns around, but at this point, it's hard to predict Dorion being part of the plan with new ownership. So it'll be up to the new GM to make that decision, and it's not inconceivable that they'd want to spend the ~8M in a different manner.
The sunk cost fallacy won't exist with new ownership and management.