Excellent OP.
Asking a tough question usually gets the same simple minded nonsense reply from the right wingnuts. One has to realize most wingnuts see the world in so limited a way, their life with mommy and daddy and uncle George is all they can see. Asking them to jump outside personal reality for the big picture is asking too much.
If the wingnuts examined their own premises put forth above, why would they complain so much about immigration and the growth of bureaucracy in government. If space and resources are unlimited why measure anything, why even consider taxes, surely they could just make more money? But again I repeat you ask too hard a question of the 'contented class.' Surely a few immigrants won't spoil the porridge. (Weird but I already know their reply

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Consider too the recent crash caused by the very ideas and theories put forth by the wingnuts on the right, if growth were so wonderful and infinite, why the constant economic crashes? Particularly after republican wingnuttery? Why is it necessary today for husband and wife to work? And why do the wingnuts not live genuinely pro life, and have lots of children? Resources are unlimited aren't they?
Geologic time is long and life is short, trying to get the narrow minded concerned and interested in a sustainable life style is difficult if not impossible. We see only so far. I watch dumps along the Delaware grow to mountains and I wonder when they will stop, but today some people do recognize limits, it is only saying so that bothers the nuts on the right. They need a foe to feel real. The frame needs to be changed as children's thoughts are established early and rarely change.
It is good to see grasslands off limits, farm areas set aside, suburban sprawl slowing, wetlands protected, national parks protected, man's greed and stupidity are infinite but thankfully some see a cleaner and more beautiful future. Anyone who wants the crowds and turmoil of China, India, or other third world nations is free to travel. When these nations use resources as America does we will have some interesting dilemmas.
Check out Derrick Jensen's work for a tough point of view.
Amazon.com: What We Leave Behind (9781583228678): Derrick Jensen, Aric McBay: Books
See also "Planet Earth" by the BBC, an excellent picture of the changing scene.
"Globalization creates interlocking fragility, while reducing volatility and giving the appearance of stability....We have never lived before under the threat of a global collapse. Financial Institutions have been merging into a smaller number of very large banks. Almost all banks are interrelated. So the financial ecology is swelling into gigantic, incestuous, bureaucratic banks – when one fails, they all fall. The increased concentration among banks seems to have the effect of making financial crises less likely, but when they happen they are more global in scale and hit us very hard. We have moved from a diversified ecology of small banks, with varied lending policies, to a more homogeneous framework of firms that all resemble one another. True, we now have fewer failures, but when they occur...I shiver at the thought." Nassim Nicholas Taleb