(Author here) Across several city blocks, in fact, and longer than the max range of Ethernet on normal (Cat 5/5e/6) cables.
Past ~300ft/100m, you need a repeater even for Ethernet. We would have needed at least one repeater somewhere along the line, which adds even more cost and complexity on top of needing to get permits from the city and approvals from all the neighbors in between. Anyone that says "just go get a permit from the city" has never tried doing it.
As for cable, you'd use fiber optic. There is really no need to go with copper in such a case.
Other than that I'd agree about your solution being optimal back then, and now. Btw how did you check the power brick, peak to peak voltage measurements? Bad capacitors is likely the single most common failure.
Past ~300ft/100m, you need a repeater even for Ethernet. We would have needed at least one repeater somewhere along the line, which adds even more cost and complexity on top of needing to get permits from the city and approvals from all the neighbors in between. Anyone that says "just go get a permit from the city" has never tried doing it.