Soccer's ratings on TV in the United States are an odd thing. The best teams play at poor times for high ratings, though the Champions League final did pull in 2 Million viewers. MLS struggles and only pops over the 1 Million viewers mark for the MLS Cup Final. Mexican league and playoff matches draw strong numbers (2.3 Million for Fall Final), but only on Spanish language stations and are often afterthoughts within the greater American soccer community. If you total all the club soccer being watched in America on a given weekend it would be a number on par with any sport but football.
But that's not how ratings and popularity work. Fans of Chelsea don't necessarily watch Club America, or PSG, or Toronto, or LA, or Santos. The lack of a league with national scope both on TV and in major markets for a significant period of time probably hurts TV ratings for soccer in America. The diverse number of options in our modern media environment also likely reduces the potential for strong numbers. In English there are soccer games on Fox stations, on NBC Sports Network, on ESPN, on GolTV and soon to be on Al-Jazeera Sports as they launch a global sports network. In Spanish there are nearly a dozen different networks carrying games.
Some would point to great numbers for the last Gold Cup Final (nearly 1 Million in English and nearly 9 Million in Spanish) or the World Cup, or the upcoming Euros and Olympics to point out this sport is popular and that MLS ratings should be higher. But these ratings are strong for two reasons - nationalism and unity. Neither of those exist in club soccer.
Four or five generations grew up in the television era. Almost all of those people are attached to their nation stronger than they are to any team. In the United States the furthest TV watching connections go back two generations at most.
Patience isn't the only solution, though it will help. When Arlo White was on Nos Audietis he mentioned a combination of quality presentation and patience, rather than watch current ratings. There's a large amount of truth to that. Another part will be soccer fans that want to watch more than just the teams to which they have a connection. In other American sports people regularly watch games between teams in their league. The numbers for American soccer (a popular sport) for club soccer are low enough this is apparently not true.
Still, there will likely never be a "solution." With about 100 teams available on TV during a week fans will always gravitate to the match they care about most, while ignoring the rest. It isn't that soccer in America is a niche sport, but instead that every club is a niche team.