Because it's not going to make the investors richer, which is what most alignment work focuses on -- how do you make its output palatable enough to avoid embarrassing customers. The entire focus of the AI industry is pumping up the dollars coming into the company, and if you're not contributing to the bottom line, your neck is on the line.

You haven't explained why investors make more money by spending money on people to solve trolley problems.

Because 1) ethics aren't universal. It's perfectly easy to frame ethics for the outcome you want depending on your a priori assumptions. 2) it's blatantly obvious that the business "needs" will supersede any ethical concerns or the ethics will be framed in a way that aligns with the primary goal of gaining money and power.