I'd love to stop renting a damned modem - it's not as though I haven't spent a small fortune over many years for routers and other network equipment.
The logjam is - we use computer telephony and most available modems don't have it. Cell reception at our house has NEVER been anything but awful - we often have to give access to our wi-fi to technicians so they can use their phones. So - we depend on either AT&T - which is ridiculous - or Internet phone.
And I've never had consistency with VOIP. So we stick with what we have.
When we moved into our house in 2005, we had Verizon, and cell service sucked. On a good day, we'd have one or two bars, at most. And that was only in the living room.
The local phone company wanted so much to put in a phone that I sort of remember asking the guy on the phone (called from work) "was he high?"
We had VOIP for years. Over time, the cell service has gotten better; to the point where I think it's been 10 years since we got rid of VOIP.
Oh, and we had Vonage, which we were pretty happy with. The ding on Vonage was that they were great, BUT, they gave customers a hard way to go when they dropped the service. I don't remember having any particular problem with that, but that was the only thing anyone ever said against them.