Because if there was actually a shortage of $80k employees the salary would increase. There is no better way to determine where there’s a shortage than the salary.
That is categorically not how salaries work. SWE compensation is high because impact per worker is high, and because adding people doesn’t scale linearly, not because they’re somehow much more in demand.
There is shortage of world class CEOs in America. If we talk about Fortune 500 (the only ones where CEOs make a bank) - there are literally less than a thousand people who are or have been CEO of such companies. If we accept immigration system premise (you are qualified and are in similar role outside US right now) the pool of available candidates is likely few dozen people worldwide. The fact that millions of people may want that role is irrelevant as they are not qualified.
MBA education system is irrelevant too as it does not produce CEOs - it produces L4/L5 PMs few of whom after 30 years of stellar career will climb to be CEOs.