They're batch processes, done by dedicated payroll firms, since there are lots of tax/other obligations as well.
Missing payroll by even one day causes 1) lots of drama with employees 2) starts some legal problems 3) potentially screws up people's healthcare/other benefits 4) potentially causes tax problems. Some of this is with the state, some federal.
Payroll is basically the second to last thing you want to miss (certain government obligations above it, since they have liability for the officers directly).
(This is mostly because employers are presumed to have a lot of power vs. employees, and generally do, and there have been a lot of historical abuses of companies paying people slowly, withholding wages, etc., which puts the employees in a position of "do I quit and guarantee I don't get paid, or do I work a little bit more and maybe collect what I'm owed" and then companies continuing to abuse it...)
https://www.ottingerlaw.com/blog/wages-hours/employer-not-pa...
Severely is overselling it.
(And if any terminal paychecks are late, there are greater penalties – waiting time penalties equal to an average days pay for each day of delay up to 30 days – though I don’t recall if there is a wilfullness condition or modification to that.)
2) What on earth does this have to do with running payroll late?
“Established precedent” is…not a fair description of action which is being challenged in the courts, where no precedential legal decision has been made.
Also, firing employees would just make the California rule requiring immediate payment of final paychecks, with waiting penalties of 1 days pay for day of delay up to 30 days, applicable, as well as triggering other time-sensitive legal obligations that a company without access to cash might not want.
Plus, it means that once you get access to your cash again, you don’t have the employees (and might have a lot less positive image in the community you would want to hire from to replace them.)
Unless it is at least willful, its probably not a crime. It is, however, generally illegal and carries a civil cost even when not criminal.
The US largely does payroll biweekly (every two weeks). Sometimes weekly, although usually not in tech. It isn't like Germany or whatever where payroll is only once a month.
Weekly, biweekly, monthly, and semimonthly are all common; In most states, there are rules setting minimum frequency (and sometimes regulating on what days as well as frequency), and they may vary by industry and job type. E.g., for California: https://www.dir.ca.gov/dlse/faq_paydays.htm