ATCO shortage?
Guess the word "acceptable" is infinitely dependent upon circumstances. What is acceptable to one job applicant may not be to another. Similarly, the ability of all airports to pay ATCOs big dosh should never be taken as a given: they don't all have the same amount of revenue coming in. It's oh so easy to bash accountants and airport managers but they too have to make sure their airports stay in business, keeping shareholders, customers and staff happy.
There are fully qualified ATCOs out there who are actively looking to switch jobs and locations, for sure, but it's up to ATS managers to ensure they get the right people. Simply having a current licence with ticks in the appropriate boxes is absolutely no guarantee of getting that vacant post:
"attitude", "enthusiasm", "effort" and "background/cred." count for plenty these days, I assure you.
Ab-initio training costs may be prohibitively high too for many non-NATS units, especially if they "take a punt" on a candidate, rather than having them screened professionally. That said, as an industry, we've got to bite the bullet and invest in new starters. We can't go on poaching off each other for much longer, I suspect.