A doctoral degree will certainly only help you to become rich in an idealistic sense. The first contract for a PhD position should have a term of at least one year - after which, graduates are rewarded with their first salary increase.
There's no doubt: Product managing directors are in demand. For graduates, this is an advantage, as opportunities for entry and career opportunities in the field are good – as is the salary.
Development engineers are problem-solvers. They work out why something does not work and make it work again.