I suspect COVID is a big factor for casuals in particular. It seems like the crowds these days are almost entirely die hards. I'm trying not to concern myself about attendance too much this year; I'll wait and see what things look like next year. It doesn't seem like the team is making much of a marketing effort this year either, like they're just writing this year off.
Setting aside the quality of the actual team for a moment, if they don't start next season with a very aggressive ramped up marketing push to try and get people back to the stadium at all costs, then I'm not sure what the future holds except for an eventual decline to a Chivas USA-style fade out of existence.
Living in the city, it's been tough the last few years to get people to come to games. Before the pandemic you had the WTC PATH weekend closures, which made it incredibly annoying to get to the stadium. I did it every game because I love going and would probably continue to no matter how much they suck, but it's tough to ask casuals to do that. This year of course there's the pandemic factor. With PATH back to normal at WTC I've been getting from my seat in the stadium to my home in Brooklyn in an hour. Not bad at all. Add in that there are more bars near the stadium to hit, the improved Harrison PATH station, etc., there are a lot of reasons for people who tried a game several years ago and haven't been back to give it another shot. But the team has to do something to actually convince them to come. Winning would certainly help.