Is "training new employees" a part of the job description? If so, then it's not an extra responsibility.

And for the record, I agree that workers should be fairly compensated for their efforts, that corporate greed is a problem and record profits shouldn't be the highest priority. But if someone has a lot of seniority with the company or years of experience in the trade, then hopefully their pay reflects that difference.

Plus, if young people aren't being mentored by the older generations, then that means they would have to go elsewhere and pay to receive instruction outside of working hours. So that's still extra work, and another way to outsource company expenses to the least financially stable.