I suspect the construction quality is so bad because our building warranties are so laughably short compared to the expected life of the home. Iirc most states, the builder is only expected to warranty homes against major problems for up to 6 years, and it's up to the homeowner to chase down the builder (who may have gone out of business in a meantime).
If your typical family home is meant to last 30 years, the warranty should last 30 years.
Because that's where the most active NCD community is.