Pitmountainpony
If you're talking about the US system, then I can understand your comments to a certain extent. My understanding from American parents is that a lot of childcare in the US is pretty poor quality. That's not the situation here in the UK, where the majority is good or outstanding - and that includes childminders.
It makes no difference whether or not you regard childminders as professionals, especially if you have no experience of British childminders: in this country, they are professionals and do a great deal more than simply watch over the children while they play.
Another problem with your co-operative model is its exclusivity. You mention a lawyer, a biochemist etc (incidentally, those professionals can't afford childcare? Really?). Where are the shop workers, the gardeners, the hairdressers? Are they admitted? Sounds more to me like privileged, well off parents avoiding childcare fees.
In the UK, nurseries and childminders take on children from all kinds of backgrounds.
In this country, of course, they'd have to be pretty well off to afford the hall hire and insurance!