Not sure anyone would ever be able to prove causation, but it would definitely be interesting to look at. For all I know maybe it’s not a factor at all?
Alternative is lower margins, but they aren’t that big in typical development projects anyway (in normal times)
They have excellent general contractor skills, but no experience in whole house construction. It has already been an interesting ride (as of now, they have dealt with soil conditions and dug grade beam trenches for the garage foundation), and there's still 98% of it left to play out over time.
- Dollar cost was 1/4 to 1/3 what a builder estimated. (Labor savings)
- I saw continuous progress with no surprise delays.
- It was easier and cheaper to do custom solutions or adjustments as unforseen issues came up.
- Was fun and I learned a lot.
Minuses:
- Material costs were higher than if contractors bought due to retail purchasing.
- It took over a year, versus 5-6 month estimate from builders.
- Was a lot of personal time and learning.
Depending on how they actually worked in practice, it may have taken them a year too.
There's also the very subjective tradeoff between opportunity cost of taking time off from my career vs the benefits of doing more manual labor and learning a lot building a house.