I think it is truly questionable that large dense populations (which JW doctrine insists upon because of the resurrection of practically everybody who ever lived in the past) would NOT be sustainable without today's industrial infrastructure.
Although both the JWs and many pro-communist liberal thinkers hate it, the "green revolution" probably kept many millions of third world residents from starving to death in the 1960s and 1970s, and this is not possible without the industrial world of modern fertilizers, pesticides, and farm machinery. (note - the JWs hated it because it potentially diminished their sick hopes for famines to prove the time of the end - liberals and communist sympathisers of the day hated it because it had the potential to feed hungry third world people and thus reduce their enthusiasm for communist revolutions).
Note too, that if you believe in Global Warming (via man's industrial CO2 profile), in this theory the industry-free earth could be several degrees cooler in such a paradise worldview - thus reducing further growing seasons and agricultural production.
Of course, the non-logical JW answer to such logic would be: "Jehovah will provide everything we need". Probably extending to making the coffee beans and cocoa grow in even sub-arctic climates, quadrupling primative farming yeilds, etc. You can explain anything with miraculous acts of God.