It's not like ALL fabs can produce a particular ASIC, right?  There's some
pretty vendor dependent stuff under most of those (unless you mean that
they're full custom chips, perhaps.  ASIC can be an overly general term.)

I don't have any trouble believing that a wildly successful product could
have tied up vendor XYZ's fab capacity, or even all the "silicon foundry"
fab providers, but it seems unlikely that they could have tied up ALL the
ASIC production capacity.

BillW