The Mariners could easily afford to spend much more on player salaries than they currently do and they would still be very profitable. The Yankees and Dodgers are consistently 2 of the most profitable teams in baseball while also spending the most on player payroll and paying $150 million in luxury tax.
There's also the safety net of revenue sharing in baseball, which makes it extremely difficult, if not impossible, for MLB teams to actually lose money.
The Mariners aren't remotely close to being in danger of spending more than they take in, nor would they be if they chose to spend more on better players.