I think that multicore support is unlikely to be the crucial feature that cements the success of the language of the future for simple CRUD web apps. Such apps are invariably not CPU-bound. Wide support on hosting providers, tooling, ease for novices, database access, etc. are far more important--which explains the success of PHP in the first place.
You're assuming that simple CRUD apps will still be interesting in the future. It's possible that future apps will be CPU-bound.
It would be nice to have a language that lets you prototype quickly but also build the real deal efficiently. Actually, not having such a language should be embarrassing for the software industry.
Multicore will drive the development of languages in general, and this will bring with it the libraries and ecosystem.
So if you're stuck in limbo trying to "make the right choice," concurrency is the feature that you should pay attention to because it will bring the dominant language in years to come, even if the CRUD devs don't use it directly.
And who knows what the basic Web app of the future will be, it may not be CRUD forever.
