@fresco,
Not sure about Bohm. but when you go all the way back to Sir Isaac Newton, that's easy enough. People of his generation -- and even more so of preceding generations -- no doubt
started with alchemy and astrology as their fields of study. What was "esoteric" was turning astrology into the genuine science of astronomy and discovering some unexpected results from their dabblings in alchemy, which, in turn, led to the development of modern chemistry.
People like Copernicus, Kepler, Tycho Brahe and Galileo were astrologers first. They became reluctant astronomers and physicists (and some, like Galileo got into serious trouble because they wouldn't accept anything
a priori but insisted on verification of observable facts). Newton was a direct inheritor of the traditions these earlier practicioners of what was then called "natural philosophy" had established. In Newton's own time, what was "esoteric" about his thinking was his outlandish notion of the theory of gravity and related matters. His contemporaries would not have seen anything esoteric in his attempts to transmute base matter into gold or to discover the philosopher's stone.
How does this relate to your original question? Perhaps Bohm and others of his ilk are merely thinking in new tracks. To them, their thoughts on matters that seem to veer away from physics and into the metaphysical may not seem esoteric at all. Dare I say, new directions for a new era? (We are in one, you know.)