Why? Just make it an add-on like HBO and charge whatever the price ends up being. No need to change the base plan.
I'd assume that the real profit of spending billions on nfl Sunday ticket is to drive consumers to your subscription services
AFAIK YouTube TV has like 5 million costumers
Meanwhile the nfl has something like 100 million unique viewers week 1?
Offering an add-on package is great, but the value for YouTube TV will be in substantially driving up your base