It’s going to take a sustained effort. Boycotts usually fail.
I can pretty much guarantee you that any fan who posted a video of himself/herself setting all of their NFL merchandise on fire is never coming back.
It's even worse than that for the NFL. The absolute worst thing that can happen is for a sizable chunk of their fan base to avoid watching any NFL games for even one weekend. Once these fans realize how much of an idiotic waste of time it has been for them to sit in from of the TV for 3+ hours just to watch 12-15 minutes of football, they're never coming back.
This is especially true for sports. Fans have always came back in the past.
I’ve boycotted Post cereal for 25 years. You don’t want to know how long by ban list of companies has grown to. Dozens of pages. Once on my bad list, there’s no coming off. There are plenty of alternative companies to choose from.
Boycotts do tend to fail. This isn’t a boycott...there is no organized boycott of the NFL that I know of. It’s the suicide of a brand