I don't know where you get the notion that Python is in any way deprecated. I'd hope to know, as both a customer of Python @ Google and a part maintainer of some core Python libraries there. It _is_ discouraged for large projects, but there's a ton of glue in Python and more shows up all the time.
Also, I know plenty of people that started working on non-legacy projects, and I'm working on a legacy project and find it fantastically fulfilling.
"Deprecated in production" may be taking it too far, but there's an attitude there that Python is a third-class citizen and the Real Language Of Google is C++, with Java a solid second in the context of acquisitions.
To be reasonable about it, I understand this impulse. Python is a pretty poor language to design large-scale systems in. I don't like C++, but one thing I've learned in using Scala and Ocaml is that static typing is a major asset, and that dynamically-typed programs can rot very quickly (even if written in the functional style).
Also, I know plenty of people that started working on non-legacy projects, and I'm working on a legacy project and find it fantastically fulfilling.