Ft. Lauderdale Strikers versus the Atlanta Silverbacks

I was recently in Florida and went to see my first American football match, from the North American Soccer League, one of the final league matches before the play-off, between the local side, Ft. Lauderdale Strikers and the Atlanta Silverbacks. It was a horrible match until the last few minutes when Atlanta underservedly went ahead, but the Strikers managed a late equalizer. The Silverbacks are the last ones of the league, while the tie was enough for the Strikers to make it to the Play-offs. But more interesting than the match itself was the atmosphere, and to learn about this US professional league, which is "secondary" to the Major Soccer League (MLS) in what for other fans seems to be a strange setup: there is no relegation in US soccer. Instead, it is about whom pays to be in the top league. In fact, the NASL side, Montreal Impact, will from the next season play in the MLS, not because they have ascended (they are leading before the play-offs though), but because of them having a strong financial backing.
I find this strange, and would wonder if it is a hindrance to the development of "soccer" in the USA, considering the enormous potential in the country.
Sadly, Florida has no team in the MLS, although I was surprised to learn of a distinguished history of the Ft. Lauderdale Strikers: they were an important team in the 1970s, and among its players have been the legendary English goalkeeper Gordon Banks, legends Teofilo Cubillas and Gerd Muller, and most interesting of all, the great George Best passed through the club in his late gipsy life of a career. It is thus not a club that is unused to seeing some good football, although that was obviously not the case last Saturday! In any case, I am now an unofficial Striker supporter.