Honestly, they need to just change it to a flag football game where guys can go have fun, not risk (less of a risk) getting hurt, etc. (the Robert Edwards incident notwithstanding). Have them get mic'd up and have it just be an fun interactive experience where maybe they also all get to walk around after it's over and sign some autographs.
Fans want to see a fun game where they can see some of their guys make some plays, hear them talk and it could even be a thing where coaches do some cool stuff with some trick plays and have it at least be entertaining. At least that way, star players won't avoid it to avoid injury and you'd have a chance to see some of the biggest names just out there having a good time. Fans will go if the players they want to see are there and it's a good experience. But it's not real football right now and it probably never will be, so it's time for the NFL to start coming up with a better way to at least make it an event people want to go to/watch.