Economists still believe in infinite growth in a finite world.
I don't think they do. It's just that many of them (the ones we hear about most, too) don't concern themselves enough with the long term that finite natural resources become a serious issue.
This is unfortunate, and it's all the more unfortunate that such "long term" issues are now not so long-term anymore, to say nothing of those that are hitting us right now.
"Sustainability" has been a key word in several areas of macroeconomics for decades. Unfortunately not in all areas of economics. Also, it was long taken in a narrow, technical meaning.