So, we take it for granted that "in reality resources are abundant"? There will be "no need for future constraints"? No matter what the population on Earth? No bottleneck resources ever?!

The current average Western lifestyle is beyond Earth's carrying capacity (for today's 7 billion) already, many suspect. We are already flaunting our tribal display to the future generations.

Even if humanity is objectively safe with resources for this century, perceptions of the concerned may matter more. The current austerity regime for the masses is indeed artificially sharpened scarcity. Would this be the first time in human history that tribal elites prefer to experiment with artificial scarcity rather than risk a cannibalistic collapse? Would #9s agree to compromise their transhumanist hobbies just to allow a billion more of fit, happy, productive people live on Earth? What if we won't ever reach planets near other stars if we dig into planet's oil resources for another 50 years like now?