$9,000 salary in 1970 would be $75,000 today

That's actually in the range of what contractors make today.

Some sources:

GLassdoor: 67k https://www.glassdoor.com/Salaries/contractor-salary-SRCH_KO...

Finturf: 75k https://finturf.com/blog/how-much-do-contractors-make/

BLS: 91k https://www.bls.gov/ooh/management/construction-managers.htm...