I worked for 7 years with the same language and tools, but lately, I can't tell which language I'll be using next week. And I love this.

But if I hadn't been a specialist in something at some point of my life, I don't believe I would be writing good code in those new languages. And I still think it's better to have at least some specialists on the team too, because sometimes you get some bizarre bugs that someone that knows the language for some time may be used to.