Looking at salaries of professional Soccer players in the US vs. salaries of other professional sports players is indeed very telling. I suspect most natural athletes can play whatever sport they wish. So why play soccer for $60k when you can get so much more in another sport?
Personally, I love soccer! I was raised in NJ and had the privilege to see Pele play for the NY Cosmos. Now I live in north Texas and have become a FC Dallas fan. I have been to see several matches in Frisco and I DVR every match I can. I don't see how people think soccer isn't exciting. I'm on the edge of my seat for every game! Please, just don't tell me the outcome of a game before I get a chance to watch it! Grrr!
Times and attitudes do change. Soccer and MLS are getting more popular in the US. More teams are being admitted into the MLS all the time. Who knows? Maybe they will be able to break whatever invisible wall is holding them back. Maybe not.
But I will say that the NFL are doing themselves no favors by having highly paid athletes "Taking a knee" to disrespect their own country in protest. Please note that they are protesting their own country, that gave them the opportunity to become some of the most highly paid people on the planet. If NFL fans continue to abandon that sport, hopefully, some of them may find a home with MLS.
That's great that you've stayed an active fan. It's a wonderful sport, even if it's somewhat like watching minor leagues.