DSL has something called vchannel. The vchannel is the equivalent to "muxing"... except there are a possibility 65535 vchannel per head end at the maximum per vchannel being something like 6.3Mbps with control. Many vchannels can be combined or bonded for higher rates (theoretically), but there is not a single provider doing that. Mainly there is as they say "no demand" for DSL Bonding, but plenty of T-1, partial T-1, Fiber... etc...

I can't imagine WHY this is... with DSL being typically easier to support and easier to setup and use less infrastructure... pair of wires per vchannel (some DSLAMs can even run multiple vchannels per pair too), and a coupla of T1 installs having to use 16 pair... Nah, never...

But, needless to say, it is beyond this discussion place.