The problem is that php itself has been undergoing a lot of change in the past 4-5 years, and tbh, even symfony 2 is not the "coolest" PHP tech out there. In php land, laravel 4 is the rad thing these days, and from the looks of it, its gonna stay that for several more years.
And since its new PHP, most of the people using it are not those who are into "new" techs, per se, but those who used to CI, or Kohana, or Cake, and avoided Symfony because of its blatant copy of Java ecosystem. As a pretty decent php-dev, I can surely say that php 5.3+ can be easily used to create better abstractions and tool-kits than Java.<p>Also, If you haven't yet, take a look at composer and packagist. Their are several cool php libs up there.<p>I am also pretty interested in knowing what are you doing about this problem, because my forte is php and JS, a bit more better at at php, and i am pretty confused about which tech to make a product I have in mind in.
Since its a distributed system, PHP might offer a better reach (also because of its popularity as "easy" amongst non-devs). But JS over node is a much better lang to work with, though it would hinder getting talent and traction and would require huge amount of marketing etc.