Fuel is the lowest cost we have with our RV. To travel 1000 miles it makes little difference whether we spend $300 or $400 for fuel. Add your costs to buy the RV and its yearly depreciation and interest if you financed the purchase, cost for storage, cost for campsites, costs for maintenance and repairs, and your fuel bill for the year.
Fuel was cheap at $4.00 a gallon and low enough that most people never gave a second of thought to getting a more fuel efficient RV or even of slowing down to the posted speed on the freeway or lightening their load, including their tow load.
We also neglect the cost in human life and environmental degradation with our wars in the Middle East that cost trillions of dollars and the cost for fracking in the USA and the loss of drinking water in many communities.
Ignorance is definitely bliss for a great many in this country.