The ROI is billions added to their valuation. Also of course it costs OpenAI much less than API pricing for inference.

The ROI is probably billions of increased pre IPO valuation.

I am curious who if anyone will get a reward for this. It would seem unreasonable to give it to the worker who asked the robot to solve it.

the ROI of new closed form solutions to navier stokes is the amount of compute used on CFD for relevant situations, along with all kinds of maintenance and design cost for making things with fluids.

the value to the researcher might not be all that big, but the value to the economy at large is gigantic

This analysis implies the only benefit to resolve this problem is to win the prize. But the prize is only there to indicate that this is viewed as an important problem in mathematics.