Allan, as an evolutionary biologist, I disagree. Yes, our basic moral instincts evolved as part of our nature as social animals. But modern (meaning, post-invention of agriculture) situations are far more complex than the simple scenarios that applied for most human history, and this requires more than small adjustments. Hence the need for philosophical thinking, not just laboratory experiments.
Also, Foot introduced trolley dilemmas in order to criticize, not support, the notion that simple thought experiments are useful in ethics. For a funny version of that criticism, see a famous episode from season 2 of The Good Place, summary here: https://www.theatlantic.com/entertainment/archive/2017/10/how-the-good-place-goes-beyond-the-trolley-problem/543393/