If someone wants a sports pack on the Flex Pack, that means that they want the flexibility to add and remove those sports channels at will. (For example, only subscribing during their favorite team's season, or even only when there is a specific game that they want to watch, and then drop the channels the rest of the time to save money.) Unfortunately, the negotiations are not about what the customers want, but rather what the RSN's want. They want the guaranteed revenue from those subscribers who want the RSN's (and ideally even from subscribers who do not want the RSN's at all) year-round, without the flexibility to remove them from the basic packages.
I think I disagree about your hypothetical $1 increase. I would hate to see the increase on channels that I do want to watch, because then I would have no choice but to pay it. If channels that I do not want to watch increase by $1, then I could drop those channels to save money (or I would have already dropped those channels before the increase took effect) so that way, the increase would not affect me. (I know that the current bundles do not necessarily work that way, but that is the way that they should work in an ideal system.)