I completely agree with you OP. Our nursery doesn't up its rates, but is blunt about the fact that it offers the 'free' hours only as a discount (of £43/wk) on a full time place (£240). Ok, so it's a little cheaper, but they are not abiding to the law as there is no way for me just to access the free hours there.
I don't agree that we should be grateful for the scraps the govt and nurseries throw us. The cost of childcare in this country is an abomination, and I am sure that some nurseries are turning a healthy profit, and that day rates are pretty much pegged to local earning power so are the highest the market can bear before parents say, fuck it, I'm better off not working.
My friend moved from London to Norfolk. Her nursery bill reduced from £70/day to £28/day. Same staff ratio in both places on minimum wage - so why the high London rates? Because they CAN charge more, and know parents are shafted.
We need a childcare economy that isn't driven by profits, which is properly subsidised, and where those subsidies are used fairly, and not exploited by nurseries who have us over a barrel. In Germany, where their economy seems to be doing a lot better than ours, a full-time childcare place will set you back about €100. Here, for many people, childcare costs are equal or greater than their mortgage.