The biggest advantage that Matthews has in Toronto is endorsements, it’s reported that he makes about 3.5 million per season in these alone.
Based on His Existing Salary, going to a team in a more tax friendly market would increase His Net Income by approximately 1.2 Million. I cannot imagine that the endorsement deals in Tampa, Vegas, Dallas or Seattle would be close to what he is making in TO, so his annual net income would probably close to the same amount.
https://www.capfriendly.com/income-tax-calculator
Allowing Matthew’s NTC to kick in without an extension worked out was not a smart move