Latency is often better than Cable ISPs and DSL (even with VDSL2 or Fastpath) on a WISP, and can easily compete with Fiber in terms of latency (wireless has less latency than optical glass), but where it falls down is in suburbia, where there isn't enough customer density to justify small cells and pole attachment costs don't allow you to feasibly put up nodes to blanket the neighborhood.
Clearwire ran into many of these same issues, but they were able to operate at two orders of magnitude more power than most WISPs can (1 watt vs 150 watts) and had way more bandwidth around 2Ghz to work with, all of which was pristine.