It's a simple metric to calculate, it's also gamed a lot exactly because of this assumption.
It's extremely faulty to measure general living standards, a country with expensive healthcare will generate higher GDP while having a sicker population, the same repeats for any essential service to quality of life which is fraught with middlemen, each step in the chain increases GDP. Also for shoddy construction, repairs and renovations will increase GDP.
Using GDP as a proxy for living standards is very poor.
And why shouldn't they? I would expect the components of GDP to correlate with living standards even if GDP does not measure it as accurately as possible.
It's extremely faulty to measure general living standards, a country with expensive healthcare will generate higher GDP while having a sicker population, the same repeats for any essential service to quality of life which is fraught with middlemen, each step in the chain increases GDP. Also for shoddy construction, repairs and renovations will increase GDP.
Using GDP as a proxy for living standards is very poor.