Intel itself has to haul all consumables for their US fabs in Arizona from Asia.

So, add few more billions for the uncertainty on the supply chain side.

Plus, having a 2-3 year project deadline looks to me as feasible, but still very tight. TSMC's 5nm fab in Taiwan has effectively took 4 years given that they still in the final stages of setting up its internals. In US, they will have to do all of that without the massive support of Taiwanese industry, and no local expertise.

Also, by completing a 5nm project 3-4 years from now, who they will be selling the capacity to, when biggest cash cows will move to 3nm, and there will be nobody to take their place for existing 5nm capacity? The cost of tapeout on 14nm is already so extreme that leaves only around 30 companies globally in the game, it will be much worse for 5nm.

Now, the biggest showstopper — TSMC is a public company with a lot of pension fund, and sovereign fund type investors. How they are going to make them swallow that? Them saying that out of the blue will be a bombshell.

Lastly, Taiwanese government has long subjected its semiconductor industry to zealous supervision, and policy guidance. Such move will have to pass by the regulators, which Taiwan has many.

So, without US government putting at least $20B cash, and big guarantees on the table, the project seems to be in the same gimmick rank as Foxconn's Wisconsin plant.

Commercially, it makes not much sense to me unless something really surreal is happening on the political, or financial side of the matter.