I think it was Diamond Sports that didn't pay the rights fee to the Diamondbacks and Padres, not the other way around.

Diamond Sports went bankrupt because they had overbid on the rights fees at the same time that the Regional Sports Network business model was crumbling. They weren't bringing in enough money from the shrinking pool of subscribers to pay the huge rights fees they'd agreed to. Diamond Sports skipped their payments to the teams and hoped they could renogotiate the deals in bankruptcy court. Instead, the teams were able to get out of their deals with Diamond.

But yeah, to your point, the entire media landscape has shifted dramatically as folks drop traditional cable TV packages for online services. It wasn't that long ago that channels like Marquee and CHSN would have pulled their content from Comcast rather than accept placement on the most expensive programming tier. RSNs made tons of money by demanding placement on the base lineup that all cable subscribers to pay for. And conversely, cable companies like Comcast could expect exclusivity -- sports fans had to have a cable TV package to watch RSNs like CHSN and Marquee. There was no direct-to-consumer option that bypassed the cable companies.

We're in a whole new sports media world and the change is just beginning.