Yeah, they will game the system
But if it caps rampant greed to a manageable level, fine. We need the new fabs more for resiliency than pure profits, or they would be built someplace much cheaper than the US.
That said I am glad there will be at least a semblance of a backstop to us footing the whole bill and them keeping all the profits. And if they choose a sane price point, no perverse incentive to fail, as they can still make more money by succeeding and paying a cut than failing(hopefully).
And especially if these Fabs get used for their intended function, providing continuity of business for TSMC in the event of a invasion from China and a need to be able to fill the US markets critical semiconductor demand, the profits from those Fabs could be extensive.