This sounds like a dramatic underestimate in the case of heavy infantry (a legion).
Elite infantry units similar to Scipio Africanus' legions went from Tarraco to Carthago at 26 miles per day forced march which is a pretty high rate of speed [1]
Using the excellent Orbis site from Stanford [2], it is possible to calculate this at accurate detail @ ~179 days marching 30KM a day, from Tarraco to Alexandria, which is across the empire.
Comparing that against an armored division, it would depend on which armored division since some are more road capable and limited mainly by fuel supplies. An M1A2 can go on roads at 45MPH and has a range of 265 miles.
[1] https://www.academia.edu/4825296/Observations_on_marching_Ro...
Reading https://www.rand.org/content/dam/rand/pubs/monograph_reports..., page number 29 (page 53 of the PDF), it seems many would break down if driven only 375 km. That’s less than the range you claim they have.
That’s one reasons why tanks, when not in action, get transported on trailers.
The text even says “significant numbers of failures were recorded during months with zero usage”, indicating that keeping a M1 parked isn’t easy, either.
> That’s one reasons why tanks, when not in action, get transported on trailers.
While that may be a minor reason, the actual big reasons are the most current M1A2 SEP tanks at ~147,200 pounds destroy roads, convoy operations are a giant pain, tanks are an immense hazard to trucks and cars, and the fuel consumption is off the charts, making this not economical.
> The text even says “significant numbers of failures were recorded during months with zero usage”, indicating that keeping a M1 parked isn’t easy, either.
Zero usage doen't mean that preventitive maintenance checks & services cease. Given that even idling a 1500hp turbine for maintenance is a major undertaking that is a good amount of start/stop and usage of the entire system, even if getting no road time.
The existence of a warlord tendency isn't totally abolished with capitalism, it is only mitigated by pressures to conform which is problematic for modern society versus Victorian or 50s society because various brands or artists wish precisely to stand out.
There is no way for anything to ultimately be a benefit to society without any understanding that one is part of a greater whole, which will be an interesting argument to present to anyone involved in designing curriculums.
Inertia isn't the problem, failure to take responsibility is. Although it does seem like inertia, a cornucopia of policies that can't be coped with, such as wastage that everyone turns a blind eye to, gradually increasing deficits of supply versus demand (for the Soviets it was grain (somehow Russia is now a grain exporter), for the Americans it is potholes).
Numbers are worthless, most Romans were illiterate, and they didn't have Arabic numbers. Bafflingly illiterate workers and automated machines are economically equivalent, otherwise there wouldn't be such a difference between high school dropouts and graduates in work productivity.
"The cause"? A failure to tolerate ambition, even when society converts into a fishbowl where everyone is neighbors. Unless ego is abolished and the most horrifying of social engineering programs could be enacted, the problems of late empire are simple: men like Robert Moses, condemned by equally corrupt later generations, are no longer permitted to ensure things run smoothly.