The lowest team payroll in MLS is actually 5.6 million
MLS team payrolls for 2018: Toronto FC leads the way, Portland Timbers rank sixth
Most teams appear to be losing money and that is with all the expansion money rolling in.
I'm sure the TV contract will bring a reasonable increase but I have my doubts that it will stem the tide of red ink many franchises are experiencing at this point. Ratings have improved, but not all that significantly in the grand scheme of things. Improving numbers by 50% or more at first glance may seem impressive, but when starting with such a low TV audience it really is not. In all likelihood, it will probably take another decade or more of similar increases before a substantial national TV contract that pays each team more then $15 million occurs.
In the meantime, teams are largely gate dependent and several are struggling with poor crowds and less then ideal stadiums (due to quality of facilities or limited revenue streams thanks to lease arrangement).
Montreal is a good example of this - they have a cheap stadium with limited high end seating options and a low season ticket base. They have been losing tens of millions in recent years and things will not get better unless a) Saputo gets tax breaks (and probably some public funds) to invest and additional $50 million in the stadium and b) there is a significant increase in the number of season ticket holders - a tough ask, given the fickle nature of Montreal sports fans.
Right now, the Impact's gate is 1/4 that of Atlanta's which likely means it is 1/2 of that of most teams in the MLS. If things continue as they are, the Impact's financial struggles will become even more pronounced and the team will likely be moved or contracted altogether. This is something the commissioner will have to address at some point - the growing competitive imbalance in the league that extends far beyond Montreal to several teams. That will not be solved by a mediocre national TV Contract. Further revenue sharing will be required to maintain viability and a reasonable competitive balance.
As it stands, it is not conceivable for the league to maintain it's health at 28 teams, as forecasted in the near term, given the trouble with attendance in many markets (numbers are massively padded thanks to massive giveaways). There is a good chance some of these teams will need a safe landing spot in the coming decade, in the absence of a significant tv deal. Expanding to too many markets eliminates soft landings for struggling teams in need of relocation.
Of course, greater revenue sharing could mitigate the financial problems of those lower revenue teams. Maybe we will have a better idea in the next 5 years when the expansion money has dried up.