It's not the pay, it's the fact that it costs far more for a person in this country to become qualified than most other places. Even nurses aren't simply trained up for the job but have to do a 3 year degree putting themselves into a minimum of at least £27,000.
Plus, I know a lot of native people who simply don't have the work ethic.
"work a 72 hour week so that I can come out with less than the checkout operator at Aldi doing a 40 hour week? Screw that" as I heard one young person contemplating studyng for a career as a junior doctor exclaim.
I for one couldn't give a rat's arse where someone comes from as long they work hard, pay their way and have a useful contribution to society. I'll happily send my native "no intention of working, state owes me a living" neighbours back the opposite way.