Councils don’t just adopt areas out of the goodness of their hearts. The developer has to pay a (significant) sum of money to the council before they will agree to adopt it.
Obviously, that comes out of their profits (although technically should have been included in the house price). If you live on an estate that hasn’t been adopted, then it’s your developer who you should be mad at, not the council.
Councils adopt areas to make money off them, which helps fund other areas of deficit. Basically, adopt the road get the house next to it etc.
I didn't think the developers had to pay the council anything, but had heard of them having to pay for schools and parks etc. I had never heard of other payments to the councils, to get things adopted, mentioned any time we've worked on a housing development, but we deal more with the services side, mainly drainage and electric. I do think this happens mind but don't think anyone really talks about it, it's kept on the hush hush, the only thing which seems to be kept quiet. I did hear these figures were going to need to be made public though, but not sure if that's happened yet.
Those payments will get included in the house price cost though, it would just be counted like all other costs, and the developer puts on 20% or whatever, and works out their house prices from that, and if it's not enough they don't do it. If house prices are dropping, the developer doesn't develop, or slows up, if house prices go up, the developer makes more and rushes to get them complete.
Developers do have to pay a lot for the roads and sewers, to get them up to adoptable standard (which get adopted by council and water companies separate), but then this seems to be trat like they just get handed over for nothing basically, as the developers have zero interest in maintaining them, and want rid of the liability ASAP. The councils and water companies adopt them as they can make more money off them etc. The councils have zero interest in roads though, but they basically adopt them to get the houses, and the council tax of course.
As for things not getting adopted or roads taking ages to be finished, this is because developers won't finish the roads (or ask for adoption) until all the drainage and other services are adopted (so they know the road won't likely be dug up again, and they have to red-do the lot), and the road is not still used for construction through traffic. On major housing sites this can be a big problem if you're on the through road, an early "finished" house, out of a major development which will take years.
I think sometimes the developers have to pay a bond too, whilst they're building, so in case they go bust, there's some money left to finish the roads off. I think where I live the developer had to pay for the local road outside it to get resurfaced too, as part of the deal to get planning, which it's been a year (since all houses completed and all internal roads finished off) and not happened yet. There is a major gas main being laid though (unrelated to the housing), so they may have been waiting for that, which makes sense as the road outside has been wrecked.
Seems a bit dodgy charging top whack council tax, when the local road isn't adopted but it's also paying for other minor roads nearby. The main A-Roads and Motorways are ran nationally through DOT/DFT, so council tax isn't linked to those.