"Lower our standard of living" is a loaded term. Imprecise. Reduce our consumption of resources, yes, that sometimes does and sometimes doesn't impact our standard of living.

E.g. Using a cast iron frying pan that becomes an heirloom passed down generations is far more sustainable than PFAS laden aluminum non-stick pans that get replaced every few years. Both can cook perfectly well.

The person living in a passivehouse premium net consumes less energy then they produce but has a comfortable, efficient home.

A city with great public transit can easily get where they need to without wasting resources on cars while reducing demand for land.

We can have a high quality of life and still live sustainably.