Haven't read the whole paper yet, but below 600 Mbit/s is implied as being "Slow Internet" in the intro.
Meanwhile, low-end computers ship with a dozen 10+Gbit class transceivers on USB, HDMI, Displayport, pretty much any external port except for ethernet, and twice that many on the PCIe backbone. But 10Gbit ethernet is still priced like it's made from unicorn blood.
My understanding is right around 10Gbps you start to hit limitations with the shielding/type of cable and power needed to transmit/send over Ethernet.
When I was looking to upgrade at home, I had to get expensive PoE+ injectors and splitters to power the switch in the closet (where there's no outlet) and 10Gbps SFP+ transceivers are like $10 for fiber or $40 for Ethernet. The Ethernet transceivers hit like 40-50C
If you decide you only need 50 meters, that reduces both power and cable requirements by a lot. Did we decide to ignore the easy solution in favor of stagnation?
If it's new construction or you already have everything ripped open it's less of an issue.
Instead we waited and waited before making slower versions of 10gig, and those are still very slow to roll out. Also 2.5gig and 5gig seem especially consumer-oriented, so for those users a cheap but half range 10gig would be all upside.
And 40gig can't reach 100m on any version of copper, so it's not like 100m is a sacred requirement.