I understand why players aren't wearing the masks. I was in the hardware store this summer, looking for a specific drill bit and for the one and only time got mask anxiety. I felt like I couldn't breath. These guys are trying to catch their breath on the sidelines, which seems like the worst time to put a mask over your face. I could see strongly encouraging it though, and even stating that players -- once they have caught their breath -- should take every opportunity to put on a mask.
If the NFL wants to make money out of this, they should sew masks into the front neck of each jersey. Players can tuck it in when they run onto the field, and then pull it out when on the sidelines. They can sell these Covid jerseys to fans, who would undoubtedly want a keepsake from the craziest season in recent history.
To me it's like life jackets, make them comfortable and second-nature and people will wear them. Nobody wants to wear the big orange life jackets and most people don't want to slip on the medical masks.