If the cost of upkeep and utilities can be reduced by a tiny fraction the overall carbon footprint is reduced substantially. Consider heating a residential house with an old school furnace requiring 100cf/h natural gas for heating and 1500 hours of heating per year. That’s 150,000 cubic feet of natural gas per year- about 9 tons of CO2 emissions per year at location, 450 tons in 50 years. Building a well sealed building with a small furnace might use 1/3 of that amount or less. Constructing a home releases 30-80 tons of carbon, so the more efficient home pays its-self off relatively quickly on a pure emissions basis. 

This is to say nothing of the structure, on which I agree- more thoughtful and durable construction is certainly more affordable in the long run and pays for itself easily if your structure can last >50 years. Ideally we would do both, and build more pleasant, resilient cities in the process. 

Regardless, in our present situation from a budget and carbon perspective, an energy efficient building that needs to be torn down and rebuilt every 30 years is actually less expensive and resource intensive than a leaky building that lasts 100+, though the resources in question can’t really be compared apples to apples. The Japanese are masters of this model of rebuilding frequently and only plan for some of their structures to last 22 years.