I think AI ethicists will be pushed out entirely after (before?) the money really starts rolling in. Ethical concerns interfere with profit margins.
I think a lot of people confuse ethics training with "don't be evil"
Manually training on "approved" ethical stances sounds a lot like censorship.
The first 10 maybe easy, but we'd see so much disagreement even without money nothing would get done.
You haven't explained why investors make more money by spending money on people to solve trolley problems.
Those left are the ones not seen as troublesome then (or those who have entered the field under them.)