I haven't been to SXSW but have paid attention to the writings coming out of it over the last few years and increasingly the opinions are that "it's getting mainstream" or that "the new people are ruining it".
It reminds me of when I was in High School and everyone started listening to Nirvana. The "early adopters" were pissed when that happened...
Ironically it's those very people that love finding what is new, different and very often great - the early adopters - that dislike when their discoveries hit the tipping point.
Without the early adopters the masses might never discover the greatness the world has to offer. Perhaps the reason they can't stand the critical mass is so they can discover something new. Begin the process again.
I think there is a significant difference between being annoying that your 'cool' community of people has gotten too large as opposed to people liking the same 'cool' band you do.
Just take online forums. Large, popular forums are much different than smaller, hidden ones. Though they both have their advantages, these advantages are different and both generally have very different atmospheres. I don't think it's wrong to complain when the things you enjoyed about a smaller community are lost as the community grows larger. Because, honestly, a community growing larger changes things, and definitely not always for the better.