On Saturday, 8 February 2014 17:24:37 UTC, David Paste wrote:
Would using coax for the last stretch to the subscriber's premises
provide any better quality of service?

Broadly, no. Twisted pair is surprisingly good as cabling for high bit rate digital.

Coax developed for analogue signals. It's good at avoiding lots of problems that affect high bandwidth analogue. When digital telephony began over the local loop (ISDN, early '80s) it was discovered that pairs worked surprisingly well and also also that the problems affecting pairs (dispersion for one) weren't problems that were quite so important to this type of signal. Closely spaced twisted pair (with terminations designed to work with it) is even better. As it's also far cheaper, this is one reason for 10baseT replacing both thick & thin coax for Ethernet.