I had to switch from Sonic (to Comcast) for just that reason. I had a bonded DSL connection from Sonic that could just barely get 10Mbps. And the bonding really wasn't even worth it because one line was at 8 and the other at 2. And it was all due to the unmaintained copper coming from AT&T. I agree with their new strategy though - the only way to have any control over their service quality was to own their own fiber.

Now, I'm in Cincinnati and have excellent fiber service from Cincinnati Bell, so it's possible to have good quality from the incumbent carrier.