I tend not to care as much about how long it takes for things that do not need R/T deadlines as humans and as steering wheels do. Propigation delay, while ultimately bound by the speed of light, is also affected by the wires wrapping indirectly around the earth - much slower than would be possible if we worked at it: https://arxiv.org/pdf/1505.03449.pdf
Enchanting that somebody actually quantified this intricacy!
My Addendum/Errata:
The alternative to a 'fast lane' backbone is not necessarily a mast based microwave link as stated, which is probably infeasible/inflexible etc.
They were mentioning 'weather-balloons' as well- which actually boils down to - I'm presuming this - the probably ongoing airborne platform internet extension attempts by Goggle/Lockheed Martin etc., you call them ...
These attempts are not based on balloons, but airships
('dirigible'-balloons so to speak), being able to stay aloft for
potentially years. That's widely known and so let's get them away,
not out for that.
NB. Airships are quite impressive for its own and therefore worth bein recherched for!!!
What I actually wanted to posit in relation to that is that one
could get sooner a c-cabable backbone sibling by marrying two
ideas: the airborne concept ongoing as outlined plus what NASA is
planning to bring about for the space backbone, e.g [1][2]. It's
laser based instead of directed radio-wave only. Sure, both is in
the speed range of c, apparantely, laser transmission has in
addition a significantly higher bandwidth to offer. "10 to 100
times as much data at a time as radio-frequency systems"[3].
Attenuations to photons in clean atmospheric air are neglible (few
mps - refractive index of about 1.0003), so actually a neglible
slowdown - easily competing with top notch fibres (99.7% the
vacuum speed of light). Sure, that's the ideal case, though, if
cleverly done from the procurement of platforms and overall system
steering perspective, might feasible.
[1] https://www.nasa.gov/feature/goddard/2017/nasa-taking-first-steps-toward-high-speed-space-internet
[3]
https://www.nasa.gov/feature/goddard/2017/tdrs-an-era-of-continuous-space-communications
-- Besten Gruß Matthias Tafelmeier