It IS used extensively for modern web application development just not by a lot of startups. In the enterprise space you really only see Java and .Net used for

It IS used extensively for modern web application development just not by a lot of startups. In the enterprise space you really only see Java and .Net used for the core pieces. One reason that Java is becoming less popular is that you don't need to use Java (the language) to be a part of Java (the ecosystem). You can use Groovy, Scala, Python, Ruby etc which are often less verbose and have more exotic features. So developers can try new languages out but don't need to abandon their existing libraries. Best of both worlds. This is the approach that companies like Twitter and Etsy have taken.