Dmiles, I'll bet you anything MLS won't ever have a national footprint like the other 4 sports do. MLS Cup won't ever be in prime time on a major over the air network like ABC, NBC, or CBS.
You must remember even established sports leagues like NBA and MLB have lost viewers because there are so many more media outlets these days and that will only get bigger in the future. There is just no room for MLS.
There MAY be a possible exception if MLS could lure a major star like Ronaldo while he's still close to his prime but I really doubt that will happen.
I agree with you on most of this. I never said MLS would be in the 'big 4,' but my hope is that it will be some day. That's just me being optimistic. You're right, there isn't much room, but that hasn't stopped the EPL gaining ground stateside (it also helps their games are on from 6 am-2 pm on Saturdays, when no other sports are on). But, I think you also have to be realistic. MLS is 18 years old. These leagues had quite a head start on it. Just after the turn of the millennium, MLS had to contract 2 teams and were down to the single digits in terms of teams. But since then, they've expanded and they're going to be up to 24 teams soon. That's phenomenal growth in a decade. My point is that you have to look at it differently than these other sports.
The wild card in all of this is football (American football). With all the brain injury information that's come out, fewer parents are letting their kids play football. Some of those kids are spilling to soccer. Yes, we've always been a 'we'll play soccer, but we won't watch it nation,' however, I think that tide is changing. I'm not saying this is something we'll see even in the next decade. But look at boxing. 2-3 decades ago, it was a behemoth sport. Now, no one pays attention. Part of that is when former champs turn into stuttering, shaky, mumbling shells of their former selves. Just like....football. Maybe it won't be soccer, but football will decline a bit and those people will turn their attention elsewhere.
Also, from 1996-2008, the MLS Cup was aired on ABC. It's since been aired on ESPN. I need to look up the TV deal, but I'm curious if Fox will take over or if the Cup will stay on ESPN over the next deal.