I agree, and am a polyglot myself, but I think there is a tradeoff.  The more time you spend learning new languages, the less time you have to master one of the languages you already know.  Take a complex language like Common Lisp.  You can learn the basics of Common Lisp in maybe a week or two, but to master the language, to really understand all the details, to know the idioms, etc, takes years.  Lisp is a language you can spend the rest of your life learning.