"Why not invest in space exploration , electric cars, self-driving cars, medical devices, green energy"
Why should they? Just throwing money at something doesn't guarantee success, and deviating from a company's core competencies can become a distraction that drags down the parts of a company that are succeeding. The dividend puts money back into the hands of investors that can choose to either re-invest back into Apple stock, or invest in companies whose core competency is space exploration, electric cars, or some of the other areas that wouldn't be in Apple's expected domain.
Why should they? Just throwing money at something doesn't guarantee success, and deviating from a company's core competencies can become a distraction that drags down the parts of a company that are succeeding. The dividend puts money back into the hands of investors that can choose to either re-invest back into Apple stock, or invest in companies whose core competency is space exploration, electric cars, or some of the other areas that wouldn't be in Apple's expected domain.