I'd suggest that #1 is already a strong part of house prices, at least in the UK (despite moving to Germany a few years ago, I've only looked at the end price here not the causes).
If you can reduce the cost of making new infrastructure to a pittance, I'd expect house prices to fall even in the absence of any change to the manufacturing costs.
If you can reduce the cost of making new infrastructure to a pittance, I'd expect house prices to fall even in the absence of any change to the manufacturing costs.