First of all, let me say that I'm very impressed by the technical work of Taylor. He does an amazing job with Laravel. Building a framework on top of existing building blocks is smart and allows him (and the community) to build higher level of abstractions more "easily". Unfortunately, the ecosystem was far from being mature when I started to work on Symfony in 2004. PHP 5 was not even stable yet.

Symfony started to get some attention early on as one of the very first PHP 5 framework. Yahoo! started to use Symfony early on, 2007 IIRC.

Regarding the audience, I don't think Laravel had a "big" influence on Symfony. The same goes for Drupal by the way. When Drupal started to adopt Symfony as its framework, we did not see a big change in terms of adoption of the framework, even after the release of Drupal 8. In any case, I'm very proud that so many large and successful Open-Source projects are built on top of Symfony. It validates the design decisions I made 10 years ago when I started to work on Symfony 2. Having a whole ecosystem based on Symfony makes PHP stronger IMO.