That is a cop out. You always need to train your people. I've been doing C++ for 20 years, and consider myself somewhat and expert, but if I join your team I will still need to learn a lot of things that are just how your team does it. If I also need to learn Erlang/java/go/ (pick any language I haven't used much) that only adds a short time.

Even as complex as C++ is, I can train a great programmer C++ a lot faster than I can train a future great junior C++ programmer to be a great programmer. Yes you will encounter the rough edges of whatever language often in the first 5 years, but a great programmer will be great in any language quickly. You need one expert in the language on the team for the weird complex stuff, but most code isn't that complex.