I'm sure they'll work out some form of payback. Probably partially through branding/advertising, probably building done sort of plant with tremendous tax breaks, abs with ask that potential free solar power, Tesla could build a solar water desalination plant and sell bottled Tesla water to make all sort of money back.
::zooming out to the BIG picture::
If Elon was willing to invest, and PR was basically willing to sell its soul, PR could become the real life tomorrowland resort community.
I'm dive into the high fantasy thought later. But this could be a win/win assuming both sides are willing to play ball.