Fans that are there win or lose and would rather be at the game than sell their seats. Not even talking about anyone who doesn't have seats so people who watch from home can stop being butthurt. This is about fans with tickets selling them instead of using them to go to the games. We have seen many of the same people week in and week out for the past few decades. Made some great friendships along the way. There are plenty of other fanbases that you see where the home fans show up to the games regardless of how well or poorly their teams are playing.
As for $$ as you put it - we don't spend a ton of money to go to the games. At SDS our seats were in the South Endzone which were the cheap seats (bleacher seats). After the move to the new stadium suddenly the endzone seats were prime real estate so we got seats up in the rafters for less just to get into the building. Game tickets, a 50-50 ticket (50 for $20), and an occasional souvenir cup drink, popcorn, or ice cream sandwich from the little retail pop-up shop. We pay our balance in full early each season and get $100 in concession money from the team. We have no kids and do not drink so that makes things easier and more affordable.
That's great you are financially in a position to do so, not everyone is and not a requirement for fandom. Going to a stadium and the whole song and dance isn't everyone's cup of tea (or for any long outings even), it doesn't mean they are any less of a fan.
Cardinals have never had a solid fan base because they have been a terrible team forever, most of their success in the last decade and a half, with some real miserable wtf years mixed in. If you want more Cardinal fans in home seats then the Cardinals need to stop being the same ol' Cardinals. That's it.
Opposing fans have always taken up a chunk of home seats, even in the SDS days (who had to use a college stadium for how long?? Lmfao)
Good relationships are two sided. Fans give a lot without much in return. If you want to march every home Sunday, great. It's great to have Cardinal fans than opposing, it's also the best fans for the owners. They can put in a half-a$$ effort and people will still give them money.
There is also thing as demanding a quality product. If you love Burger King and they started using cheaper ingredients to save money but their net profit increased so they don't have incentive to do better, are you still going to go there to prove your loyalty to that business because it's your favorite even if you dislike the new taste? Are you going to stop going there? Are you going to demand change? Are you even a real fan of BK if you don't keep eating their lower quality food?
In this scenario the only way BK changes is if enough people stop eating their food. So who loves BK more, the one's that keep eating it through thick and thin or the one's who don't to force the change for the better? Those that keep eating it out of loyalty helps ensure that the quality stays poor that's for sure, as long as enough do it. I would say both sides could love it just as much, they just take different approaches.
Sports are not the exact same, I understand. But just cause anyone who does or doesn't spend money or goes to games do not make a fan. It's about what's in your gut. Your heart. Your connection to the team. A bad play. A good play. The excitement of your team stepping on the field. The agony of a game losing kick. The adrenaline shot of a game winning TD. All of that and more are far better examples of a fan. But most of all they want the team to succeed.