Universities typically are in the public sector side of the equation... and the public sector doesn't pay any non-administrative role the Big Tech rate.

Pulling up my alma mater... https://www.openthebooks.com/wisconsin-state-employees/?Year...

The various roles that you'll find for software developers: Sr Is Specialist, Is Tech Srv Cons/Adm, Sr Inform Proc Conslt, Sr Systems Programmer

And you can pull up the pay scale at https://hr.wisc.edu/standard-job-descriptions/?job_group=Inf...

$80k/y isn't "we're paying H1-B half of what the going rate is" but rather "the state legislature has set this pay scale and we're paying everyone that amount" ... And many times, H-1B visas aren't eligible to work in those roles.