There's going to ba A link whether you like it or not, no matter how professional someone is. Someone worrying about how they're going to pay the bills is never going to nhave their mind on the job quite as much as someone who doesn't have those worries.
I'd agree with you if teachers were on a minimum wage, crap pension and 20 days holiday a year but their conditions are actually very good so asking them to put more to their pensions shouldn't affect their teaching.