I can't believe anyone who cares about voice quality would use anything else.
I work out of an office in my home. All of my phone time is spent either selling my products to prospective customers, or trouble-shooting the technical problems of existing customers. Neither of these groups are willing to tolerate the drop-outs, distortion, delays, echos and other issues associated with cell or internet-based phone service.
For folks like me, there is no viable alternative to POTS.
NEVER insult landlines! My naive observation was obviously not well received!
Please pardon me. I am now much wiser (even if I don't have a landline!)