What you state is an owner problem. Melnyk in Ottawa doesn't/cannot spend to full cap.
Phoenix, who's real owner is kinda a debatable subject, doesn't/cannot spend to full cap.
The cap and floor are a CBA negotiated mathematical formulas. One cannot grow without the other, not without having a major impact on pretty much everything else.
Sure a place like Toronto would survive but every single one of the 31 teams would try to fully or partially transfert those extra millions in cost to US the fans. Without knowing how much you pay for your tickets...would you be okay with a sudden 20% increase ? I know I wouldn't. The NHL is still a gate-driven league. A big chunk of it's 4B revenues come from direct ticket sales to fans (82 games for every 31 teams, at an average of 50$ a ticket and an average of 15000 tickets per game is 1,9B).
Very few teams could afford to pay a higher cap ceiling without charging more, and you already state that many teams struggle in current conditions, worsening those (raising the expenses) would only make it worse.
My argument is very simple , hockey has always been a great sport over any other sport , but the players have always been under paid . The notion about ticket prices going up is false , if a team a team is winning they automatically go up that's a given, cities impose taxes which in turn teams half to raise ticket prices.
Their are plenty of billionaire and investors out their who would love to buy into or buy a franchise that's a given.
Winning solves all cash flow issues, if your not willing to put a team out their that is competitive, you build and send a bad message to the players on the team , moral , tanking to get picks , etc, if these markets or owners can't support these teams and have a salary cap that rewards players and teams for allowing them an achievable cap to work with then instead of adding another market , either take the franchise away from bad ownership or eliminate that market.
I'm not saying over pay players, but example players who are extremely gifted should be rewarded and players , who achieve team success year after year Chicago 3 cup , 5 conference finals in 7 years those players should be rewarded and not penalized , because other markets or owners can't get their act together and other teams have to suffer the cost at their expense.
Ottowa use to have good teams , however their owner seems to be a I see along with Montreal, phoniex why did the NHL not just fold up that market when the owner created a losing attitude with being cheap which killed the market shares . Their comes a point where the league needs to rethink the salary cap and markets.