[mspaint]

>well and after all that investment the person leaves for better salary/etc

They could offer them a raise based on their new value? If this company can't pay people well or offer a good work environment, how are they going to get senior developers?

> (any NoSQL/Hadoop) can be picked in a week

I can't believe there are companies looking for people with a "week" of experience in NoSQL who aren't mid-level developers already.