In answer to your googolplex question - I think it's safer to bet on the technology developing to support such a population than against it. (Though I think we'll either be extinct or an interstellar species before then.)
My use of that population number was simply that: a refutation of the assertion that the earth has no population limit, as it will be hard to argue that our planet can support 10^9980 humans per square millimeter of land area. A genuine "argumentum ad absurdum", to counter the GP's completely nonsensical opening statement.
But instead of that, the initial reply:
- refused the basic premise that would have allowed that discussion, by indirectly positing that space on earth is infinite
- followed it up with a very questionable assertion that earth's resources are used "more or less sustainably" (which is already at odds with the previous assertion that resources are infinite, and ignores the many species we've already hunted to extinction)
- added a non-sequitur that we would have run out of resources as hunter-gatherers (again at odds with the initial statement)
- justified the plain refusal of the basic premise with an ad-hominem about bias
- continued on with the apathetic rationalization that nothing can be done anyway
- concluded by reiterating the initial statement without further substantiation
Now, you may argue that my refusal to engage in that discussion is my weakness and it would still have been possible to salvage something positive, however my time is finite and there's better, less taxing discussions to be had.
(/me out, accepting that meta-justification is considered offtopic and will be downmodded).
In the interest of (scientific) discourse, it is generally unhelpful to redefine or ignore generic definitions. Are you asserting that the earth doesn't support any species, or that is perfectly possible to have googolplex people living on earth without reducing earth's ability to support googolplex people in the future?