But Quintessentially that line of reasoning doesn't work for any other kind of service. I don't ask for a discount in M&S because i don't pay very much, or expect cab drivers to halve the fare for me because they almost certainly earn a lot more than I do. If you want a service, you pay a fair price for it.
As I said, I'm on a low income. I could have done with a great deal more childcare than one day a week (I work from home), and perhaps I could have afforded more childcare time if I'd paid shit wages, cash in hand, and not paid sick pay, etc etc. But that's no way to behave, so i paid the proper rate, and only employed a nanny for the time I could afford.