It's pretty common in amateur sports. Local softball leagues have A,B, C brackets and teams move up and down accordingly. My guess is teams started as coworkers or local sport clubs, bracketing happened, the players started getting paid. Evolution. Modern pro/rel. It's almost surprising that it didn't take hold in the US in sports like baseball and basketball.
In 1901-1902, the English First Division had 18 clubs, which is almost as many as it has now. The story of American leagues is expansion and leagues that started when there were fewer people out west. When MLB's American League was created, California, Oregon, and Washington had 13 out of 386 House of Representative seats, which is 3.4%. Now they have 68 out of 435 seats, which is 15.6%.
Just want to jump in here and say I love MLS. I follow NYCFC as my local club here in Australia is also a CFG club. I also like the NWSL. I think most matches are exciting and the overall quality is pretty good. The A league here in oz is pretty similar, started from scratch after the old league fell apart, mostly franchise style clubs and no pro/rel. And people here, mostly followers of European soccer, moan about it also. Don't understand why all leagues need to be the same to be taken seriously. One thing about MLS I like is the way fans seem to have merged what I would call traditional American sports fandom (tailgates ect) with more traditional apsects of soccer fandom(tifos,drums,chanting/singing ect). It creates a uniquie culture around the game. Also I don't notice the negative aspects, violecne ect often associated with soccer in Europe. Here in Australia unfortunately there is a small minority who like to emulate Euro "ultras"' and cause trouble that gives the game a bad name in the media, which is largely controlled by the AFL.
What I don't understand is why I can't read the comments of an MLS post without sifting through tons of "MLS SUCKS" comments. Why do tons of people like the MLS facebook page for the sole reason of writing stupid comments like this?
I don't read Facebook or comments on news articles about anything. Read BigSoccer and sports websites to stop getting "MLS sucks" comments.