Here's what I expect will happen when an average developer is "to learn C++ on the job":
The inexperienced developer will write code that is subtly wrong. The senior developers will spend more time debugging than the time would take to write the code themselves.
The new hire will effectively have negative productivity.
And when the new hire has learned enough, s/he will get a new job. The comapny will not have recouped the investment on the developer.
The inexperienced developer will write code that is subtly wrong. The senior developers will spend more time debugging than the time would take to write the code themselves. The new hire will effectively have negative productivity. And when the new hire has learned enough, s/he will get a new job. The comapny will not have recouped the investment on the developer.