It's actually not a long time in the startup world, either. The average life cycle in the valley for VC-backed startups from founding to exit is 7 years. There are always exceptions, of course. But two years isn't enough time, in general, for anything interesting to shake out--either in languages or in startup companies.
I doubt that, as well. Ruby still isn't all that popular a choice for startups, and it's had some astoundingly good marketing. I'd say maybe 20% of the startups I know personally are using Ruby, with the rest divided amongst PHP, Python, Java, and Perl (not necessarily in that order, though PHP is definitely at the top of the list by a large margin). Since RoR started gaining traction about three years ago, and RoR is still not the leading platform, the notion that Erlang could even become a contender (much less the leader) in two years is more than a little ridiculous.
Not to mention the fact that there's only one language at this point that is inevitably going to grow really rapidly in popularity (JavaScript). (Others will grow, but none so fast as JavaScript.)
It's actually not a long time in the startup world, either. The average life cycle in the valley for VC-backed startups from founding to exit is 7 years. There are always exceptions, of course. But two years isn't enough time, in general, for anything interesting to shake out--either in languages or in startup companies.