Graduate school is a great step for engineers who are interested into research based jobs.
Most bachelor’s degree will not teach you how to solve complex problems. A masters degree will give you the skills to solve a problem using literature searches, design methodology and rigorous mathematical theory.
This of course varies widely by schools, degrees, advisor and student motivation.
A PhD gives you the **chance to propose a complex problem no one has ever solved **!
It is possible to be pursuing a PHD and have a stable job outside the program or would you consider that your job? Lets say I am trying to earn a PHD at Caltech, I am doing research during the program, can I also be working at JPL? What is the actual PHD progress? You really don’t need to do the PHD process in computer science right? Just make a big impact in the world, PHD is just a title.
I’m not as familiar with the CalTech/JPL scenario however I have seen people do a similar working PhD at NASA-JSC/Rice. It is a more strenuous path especially when your taking classes.
Many people have made huge impacts on the world without a Bachelors degree. Every degree is a title. However, your PhD thesis and research papers represent your research quality level.