I'm very sure it's not nimbys, that's just governement/builder spin as normal citizens really don't have any power.
That's a convenient excuse. I'm sure the builders absolutely love cramming insane numbers of houses in, they're making a fortune from it.
There's a newbuild estate here. The houses look OK until you drive right up to them and realise just how tiny they are - they're really carefully scaled so look like decent houses that are further away! If you count the bricks between the windows and multiply by 225mm you can appreciate just how small they really are. And that's on the outside - then there's the extra-wide cavity and more block or frame on the inside.
Another thing they do is build semis where one end is turned 90 degrees, to hide just how tiny they really are. It looks like a decent sized detached house from the front, until you spot the extra door round the side. Some that look like a generous detached house are actually 3 in a terrace, there's a front door on each end.