Unfortunately, in today's world it's a great deal of homework and everday consumers don't have the time to do it. To make it worse, the situation constantly changes; someone who is knowledgeable today will be obsolete six months from now. (I think the companies do that purposely to keep people confused and benefit from inertia.)
The average person doesn't know what an "NPA" or office code even is. A phone number is a phone number. Keep in mind that neighbors that once had one or two exchanges serving them now have a great many. Depending on the service option (low, medium, high), my local calling area covers SEVEN area codes, and minor toll service (5c minute) adds another three area codes to that. That's an awful lot of exchanges to keep in mind.
Note how many regulars in this newsgroup need to discuss today's service options and debate clarifications and specifics. If "people in the know" aren't sure of the situation, how can everyday people?
In the old days a person could simply ask their neighbor and compare bills since everyone had the same situation. Can't do that today.
A lot of people use their cell phones at all times, but such service costs about $50+ a month and is subject to poor quality (last night I was talking to such a person and the reception was horrible, I could barely hear them.) I'd sure hate to need to make an urgent call and discover I'm in a dead spot or the battery is dead.
As to customer service, I use Verizon and am very satisfied with them. It's much better now that my LD is with them instead of AT&T. I'm not quite as happy with their wireless service; they buried a notice about holidays no longer counting as offpeak time in text about obscure overseas calls, but they gave me a credit for the calls I made.
[TELECOM Digest Eidtor's Note: What Sam Spade does not grasp, and what the telcos grasp all too well, is that most non-telco people do not understand, nor do they care about the workings of the telephone company. Over the past century, telco has made lots of money based on the ignorance of the general public, and they are still at it. PAT]