Almost all of these new devs work in the world of open source – the closed shop shrink-wrapped products of the Microsoft and Adobe heyday draws to a close – and public open source solutions, software and services rise to replace them. The developers of today cut their teeth on Linux and OS X and they use languages like SCALA, Python and Ruby, instead of .NET and Java.
Sorry, but that is purely wishful thinking.
Python enjoyed its own little dot com cycle all in one language - boom, bust. If you want to work for a mom & pop scale start up, use whatever you like (hell, use everything - I know I did when I worked for one), but as soon as you want to work for an enterprise scale business, you will be using .NET or Java.