With respect, I don't think that your tweet actually makes a helpful comparison.
Throwaway remarks/bitching on Twitter (guilty as charged) are always going to be easier than making a sustained contribution of time to build a community of peers around a common interest. Groups of people who are passionate about what they do and the tools they use to do it are always going to need to let off steam, and far better on Twitter than in a meta thread. But a considered conversation? Yes please...
I think a lot of good, generous people already are engaged and contributing to this nascent community, and when the beta opens to the public, I hope to see that group grow very considerably.
It's also worth bearing in mind that we are still(!) in private beta - so the total pool of people who can contribute to the site is still pretty small. According to the Users tab, right now there are ~380 users signed up to the beta, of whom ~60 or so have contributed a question or an answer in the ~13 days the beta has been running.
Having been involved with facilitating/managing online communities in a past life, that sort of engagement level is actually fairly decent. IMO our Area 51 stats also look pretty healthy for a site thats in private beta, heck they beat those of quite a few SX sites in public beta.
It's a hackneyed saying, but the community (along with the brilliant addon ecosystem - not that you can really separate the two) is what has made EE so great in the past, and I'm personally still hopeful it will be strong enough to carry us into the future as well.