I can do that easily. Give me a ~10ac property where what isn't steep is stream or bog. I want to clear ~1ac total for 5-houses on 2ac each and the road to reach them needs to cross a stream and traverse some bog (read: offsets). The houses will have to be on piles because as expensive as that is that's cheaper than cutting flat land and doing walls or offsets.

surveys and delineation $20,000 bridge $25,000 road and driveway $75,000 stormwater $40,000 Wetlands offsetting $25,000 250 Permitting $140,000 the houses themselves (remember, they're on fancypants piles) $100,000 septics (mounds) and wells $75,000

total: $500k, 100k per house.

You could cut some out by DIYing the actual permitting submissions but even if you don't make costly mistakes in wording and/or detail level there's a lot of value in having your shit cross the government's desks on the letterhead of an engineering firm who's stuff they've approved a million times before.

The developer needs to then build the houses rich af on the inside and generally check every box to sell for enough to cover the costs. This kind of stuff is why so much of the development in Vermont is rich assholes from NYC in brand new million dollar homes on the world's shittiest gravel road with the world's shittiest driveways. Granite countertops and picture windows the size of rail cars are damn near free compared to the cost of putting a shovel in the ground.