I am dumbfounded how Garber is claiming a hit of $1 billion in revenue in 2020. Don Garber: MLS is forecasted to lose pretty close to $1 billion | SBI Soccer
Sounds like BS math. His argument is that MLS depends on in game stadium revenue more than other leagues, so they are getting hit worse. But he is talking total revenue, not profit, so MLS's financial setup (e.g. % of revenue from stadium vs. sponsorship required to keep things running) is irrelevant.
Also, I saw reports that total revenue from 2017/2018 was $1 billion, and that's inclusive of sponsorships: MLS vs Premier League: Revenue, Salaries & Attendance  (wsn.com)
As an analogue, NBA is claiming a 2020 hit of $800MM to revenue from gate receipts (and an additional $400MM from sponsorship/merch issues, including China/Hong Kong/Morey fallout). NBA revenue for 2019-20 season dropped 10% to $8.3 billion, sources say (espn.com) The NBA has 2.5x as many games and 20% more teams. I don't see how MLS had greater hit from Covid and no fans at games (from a revenue perspective) than the NBA.
My guess is the bigger a hit they could tell the players (and fans) they were absorbing in 2020, the more sympathetic players (and fans) might be in CBA agreement. Gain sympathy, then exchange that for maximizing profits in 2026/2027.