It’s not a money thing. It’s a shortage of people who are mentally able to do the job mixed with terrible hours and early forced retirements. ATC school has a failure rate of over 50 percent.
It's partially a money thing. ATC is under-compensated. They'd get more - and more talented - people interested if the money made up for the stress, hours, and early forced retirement.
Or increased their hiring funnel. Air traffic controller applicants must be under 31 years old for initial hire, which rules out a lot of potential hires.