Why Limit Web Development to JavaScript?
elevatesoft.com
elevatesoft.com
I think the browser is only just starting to accommodate web developent in other languages. Until asm.js came about the advice was you had to learn js to understand runtime performance of any code running on the web and that languages that closely resembled js were easier to optimize and debug in the browser environment.
And yes, I think you're correct about things just getting started. Mozilla is trying very hard in the "web assembly" arena, and Chrome is helping things a lot by opening up their debugger for remote debugging. And, of course, projects like the CEF help a lot with embedding the browser in another development environment or IDE. It's all pretty exciting in terms of the amount of promise and potential that the browser environment brings to the table.