Green belts not sacred; profit is

One of the things that really sucks about being a conservative is that you're expected to defend the douchebags ... er, developers who ache to turn every field, meadow or forest that fails to turn a profit into something only humans can make use of.
For instance, Policy Exchange, a right-leaning think tank, suggests that Britain's green belts are "not sacred" and that the debate about developing on the green belts should be conducted in a "less emotional" tone.
Policy Exchange seems to be under the laughable impression that 90 percent of Britain is undeveloped, thus the green belts don't matter.
Well, dear non-English reader, let me explain what the green belts are. The green belts are U.K. town planning policy which controls urban growth. A "ring" of countryside acts as a sort of buffer to every major city in the U.K., such as Birmingham, Glasgow, Liverpool, Manchester, Newcastle and, of course, London. These "green belts" were first proposed in 1935 and have since become government policy.
The green belts attact criticism these days due to the fact that Britain has a booming fertility rate, mass immigration and a housing crisis. The pro-development crowd asserts that, far from running out of land, we simply need to manage it better. They claim that most green belt areas are of unremarkable environmental quality and that it's far better to have green "wedges" than belts, and to preserve those areas of country around which no major city exists.
Sounds all well and good except for the fact that I do not trust the developers. They cannot convince me that their first concern is the environment when I know for a fact that it's profit. I am not fooled.
Admittedly, the Town and Country Planning Association, heavily credited for helping to enact the green belts in the first place, now argues that the green belts encourage development on countryside outside of protected green belts. I would be open to the idea of green wedges and corridors linking people and nature if only I could trust the ulterior motives of those who argue in favor of development.
And even if it was true that an amazing 90 percent of Great Britain was undeveloped, why does that mean we have to build on it? Why can't we say, "well, that sounds wonderful, let's protect all that land we've got left?" Why is our first instinct to create more towns, more roads, more strip malls? Is it because people are greedy fuck-bubbles whose primary opiate is consumerism? Quite possibly.
I can't help but think that if only Britain would enact a tough-as-nails immigration policy and if only the remaining natives would keep it in their pants more, then this whole debate over development versus the green belts would not be necessary.