> Furthermore, if you really want a C++ developer you can just expect a developer to learn C++ on the job if they have any adjacent experience with any other language.
Yeah nope
Any language takes at least 3-5 years to fully master. Sure, the "10 years in X technology" posts are sometimes insane, but... also, there is a real, factual difference between "I worked with technology X once" and "I am working with it for 5 years".
That really depends on the language and their background.
Going from C to C++ and you can be pretty functional pretty quickly, and comfortable in a year. Your big hurdle then is whatever specific libraries you're using.
Smaller languages like Lua can be fully adapted to in about 2 months or less.
I mean, yeah, picking someone with 10 years of Python experience and nothing else, then expecting them to jump right into a massive C++ codebase won't go well. But someone with 5 years of Ruby experience and a side project in Python will probably do pretty well if they're dropped into a Python-oriented job.