I work for a Cable/ISP and this happens every two-three years.
The long and short of it is that Cable way viewership is down with cord cutters and streaming. The networks make money off advertising, but w/ lower viewership, they aren't making as much money off advertising. So the networks attempt to raise the prices for rebroadcast by the cable companies. The cable companies are also feeling the pinch from lower viewership, however, so they balk at the higher prices, leading to these blackouts and passive-aggressive messages from both sides.
My company had a particularly bad negotiation w/ AMC right after Walking Dead hit big - the station was never big in demand until then, and they tried to raise prices accordingly. It escalated to the point that AMC blocked the season premiere and instead ran a message urging viewers to call our support line and complain - even included our customer service # in their crawl.
Disney was usually pretty secure, because ESPN was the only channel that wasn't losing viewership, but that's changed in the past couple years.
ESPN was the only station we wouldn't challenge the price increases - we gave the additional costs creative bullshit names like "Sports transmission fees".

EDIT: I'm sure that Biden/FCC's new rules about hidden fees plays into this as well, as the Cable Companies can't hide the fees anymore.

Great info