Yes they could sing. As Gordon's wife said " that general era as "the era of harmonies", 60s through 70s,"
Today one group that can sing with no autotune is Foxes and Fossils:

https://www.bing.com/videos/riverview/relatedvideo?q=foxes+and+fossils+california+dreaming&mid=2962D432EB8C5A8C3AED2962D432EB8C5A8C3AED&FORM=VIRE


I get most of my exercise these days from shaking my head in disbelief.


64 bit Win 10 Pro, the latest BiaB/RB, Roland Octa-Capture audio interface, a ton of software/hardware