But there are many complications beyond that. For example, on all four sides of me in the last decade multi-story buildings have gone up. I've lost all daylight as a consequence (used to get nice yellow sun rays in the late afternoon, that's gone now). I didn't object because I know housing is badly needed, but it still rankles that they tend to put these things near less-well-off people, while the wealthy (for example those who live on the outskirts near the green belt or in small villages) have vastly more power to block such developments.
Generally, restrictions tend to get eased in places where less politicially-powerful groups live.
The high-rise blocks here were originally put in surrounded by empty green space - the argument was that as they were replacing terraced homes with small gardens, that green space was made possible by the higher density of the blocks of flats, and thus served as a sort of communal replacement for those gardens. Now, though, they are in-filling that green space with more blocks, as it's now seen as wasted potential housing space.
There's also the matter of where the jobs are. The problem that keeps coming up is that the affordable housing is all in places with no jobs, while where the jobs are nobody can afford to live. I don't understand why jobs end up so unevenly-distributed. Maybe if they weren't, people wouldn't all need to cram into the same small areas of the country?
Then there's the issue of whether its necessary for a country to be self-sufficient in food production. You could allow building on all the farmland, but then the country could be held-to-ransom by the foreign countries it would depend on to feed itself. But then again, we are already dependent on imported fertilizers to grow that food, so maybe that's not as meaningful a problem as its made out to be. I don't know.
And there's the question of biodiversity and to what extent non-human species also have a right to a habitat. Apparently biodiversity is highest in suburban areas where houses have gardens and there is a lot of open space between developed areas, and is ower in both high-density inner city areas and the supposed 'countryside' (which is mostly given over to quasi-industrial forms of farming and blanketed in pesticides). On the other hand, that high-density inner city area is much more efficient for providing services and in reducing the need for car commutes, so is environmentally preferable in that regard.