And yet, the number of on-topic comments hasn't increased, either. It's not that people are getting accustomed to beta, it's that they're leaving.
We're locked into the current two-party system by the very nature of first-past-the-poll voting. We're more-or-less locked into Youtube by its sheer mass: your average Joe doesn't have the server space or $$ to hold all that video content like Google does.
We're not locked into slashdot. We have nostalgic feelings for it, but that's all.