My understanding is that most of the "shortage" is in older processes where capacity is shrinking as fabs offline older tooling. Customers with parts that are stored as masks (e.g. engine controllers from the 1990's) or whose design teams have lost the expertise to resynthesize the HDL (again: think auto manufacturers) have very few options when capacity in these older processes starts disappearing.

Crypto hardware is generally "just logic" which means that it's (1) fabbed on fairly modern processes and (2) generally quite portable to other processes just by recompiling your Verilog and wiring it to a different manufacturer's PCIe PHY or whatever.