Apple has enough money that it doesn't matter if this research is not successful. At least they want to try this, if the result is good enough they may eventually release a car. If not, they will just consider as a lost research cost.
If expected ROI is too low they should return the money to investors (share buyback or dividends) and let investors choose a different investment with better prospects by themselves.
[1]: https://en.wikipedia.org/wiki/Principal%E2%80%93agent_proble...