It has been starkly noticeable since my company has moved from doing phone-in conference calls to using Teams just how compressed normal phone line conversations are. Combined with a couple of our members having piss poor mobile coverage where they were (but much faster internet) our meetings became a lot higher quality.

On the phone-line side I wonder if that is a degradation due to digital switchovers & compression, a lack of allocated resources, or just pure rose tinted glasses.