From what I understand at least when there is a work stoppage, the players have an escrow account that they can get money out of, but once thats done they don't get paid if they don't play. At least thats what I remember from the last NHL lock out. Not sure how that applies to pandemics.
A lot of these teams are gate driven, especially in smaller markets where they don't benefit from huge TV deals. Sure you get revenue sharing and big money from those national TV deals, but the bottom line of sports teams eventually is going to be effected by no attenedance. And I can't imagine these networks are happy with no content on. Sports is one of the highest and most consistent ratings getters, especially because its live.
The big 4 are too big to fail, but smaller leagues will be in trouble. XFL already went bust. CFL (canadian football league) is asking the feds for 150 Million dollar bail out. It wouldn't surprise me if some NHL teams like Winnipeg or Edmonton start talking about financial trouble and looking for money. I gotta imagine some smaller NBA teams are feeling the crunch.