The issue is not so much that foundries can't afford it rather that the USA was dismayed to discover that most US based foundries have moved over seas creating

The issue is not so much that foundries can't afford it rather that the USA was dismayed to discover that most US based foundries have moved over seas creating a dependence they now think is a problem. They want them back not just for jobs but also for national security reasons (as I understand it) and feel that the issue justifies the incentives. I think the issue is compounded by the fact that many countries have come to the same conclusion and foundries are not likely to build multi-billion dollar plants in each of them, so there is also scarcity in play.