There are two reasons why people who'd like to do research do PhDs. First, without PhD, it is difficult to get a job in research. At any big company or univers

There are two reasons why people who'd like to do research do PhDs. First, without PhD, it is difficult to get a job in research. At any big company or university it is pretty much a requirement and it is hard to go around this one. Not impossible, but very very hard. The second reason, is that it's the environment that makes the researcher. PhD years are essentially the years of apprenticeship, in which you are working alongside with (hopefully good) researchers. It's just like in any other field. To acquire skill set, to get good at it, you need to work for some years with people who are already good. Engineering skills are essential to a researcher, but actual research skills even more so. So if you manage to force your way in, and get a researcher job with only engineering experience (I've seen people do that), your contributions to a research project will have a chance to be on a negative side. Will even have a chance to derail the whole project.