Class G operates and relies on the requirement to "see and be seen" in order to comply with the right of way rules.
Fair point but there's plenty of aforementioned avian aviators up there doing that so it won't be long before that can be emulated.
Surprisingly, since the tragic accident on 16th January this year near Vauxhall, every man and his dog seems to be using ever taller construction cranes.
I'm not sure if accident is the right term to describe the outcome of flying VFR in blatant IMC at low level in a built up area. Drones could have advantages here from stabilisation, sensing beyond visual radiation, ability to work with hires ground models a la GPWS. And disadvantages from s/w bugs, component failures, etc
I imagine regulation and certification and maybe insurance in developed countries will dramatically hike the costs so could turn out to be a Webvan 2.0 for Amazon.