How Does One Keep The MLS Alive?

You allow NFL owners to buy in, that's how. According to Parnesh Sharma, one of the main reasons the NASL folded was because pro football owners were barred from owning soccer teams way back when. Money quote:

The second obstacle – the NFL effort against MLS's predecessor, the North American Soccer League (NASL) – is not widely known. In its heyday in the late 1970s, the NASL was a serious presence on the US sports scene. The New York Cosmos, the league's flagship franchise, had little trouble filling Giants Stadium, especially when soccer legend Pele joined the team. The NFL, then not quite the juggernaut it is today, watched this development warily. Aided by a willing media, it began to vilify US soccer.

In addition to applying pressure to newspapers, radio and television stations, and advertisers, the NFL also prohibited its owners from owning teams in other sports (an action directed chiefly against the NASL). The NASL sued, but the NFL won in court in 1982. The NASL folded in 1984.

I don't have the current NFL bylaws in front of me, but obviously, we're living in different times. As far as I can tell, NFL owners own four of our domestic league's thirteen teams.

US soccer: Commend it like Beckham [Christian Science Monitor]

-ac