A couple of thoughts about Canards: -
In cruise, no high lift devices are used, therefore there are two lifting surfaces, this is more efficient than a wing+tailplane design. If anybody doubts this, I have performance figures for my own single seat canard that knock spots off anything with a tailplane and similar weight and engine.
When using high lift devices for take-off and landing, unless you are prepared for huge pitch changes (that probably need to be automated out) as the devices are selected, it's going to be necessary to fit devices to both wing and canard - a complexity not required in the same way for a tailplane aircraft.
With a tailplane, the stall is (usually*) marked by wing stall - or in other words when there's hardly any lift left available. With a canard, the stall is (usually*) marked by canard stall - so at that point the wing could still potentially generate more lift.
This means that a canard aircraft will have a higher stalling speed, and thus a higher approach speed and thus need more runway.
So, a canard configuration defeats the airline manufacturer's desire to be able to use the shortest possible runway. This, in my opinion is what kills the idea - all the other problems could be solved if there was a good enough reason to.
G
* My "usually" is because in fact a great many aircraft have the stall speed defined by a pitch control limitation, and the wing may well still be lifting.