Fir engineering, industry jobs are the default. The main reasons that they go to academi are those who like teaching, and the fact that there is a lot more freedom in research in academia. Research in industry is constrained and determined by the needs and interests of the company, while academics have far more freedom in choosing their own directions.
Considering that PhD is, first and foremost a research degree, the ability to do the research that one wants can be a very strong incentive, which outweighs income. My wife, a CS professor, has standing offers at a number of companies (including FAANG), but chose to stay in academia, despite receiving maybe 1/2-2/3 the income that she would get in an industry position. She loves her research, and no company would allow her to do what she is doing in research. Of course, most CS PhDs make a different choice.