I certainly hope Human numbers decrease to 3 billion...and yes it will be economical hell to make such transition. Until we learn how to use it in harmony I want less "Human energy" in the Ecosphere not more and better used.
As for population collapse bellow the number I advise 3 billion, first solve the minimum standard of living so people are willing to commit to have children...starting a house by the roof is not the solution.
While I agree that the projects Ellon is in are indeed PHILANTHROPY at its best and smartest I still think that we have an epic dilemma to sort out regarding sustaining humans both physically and mentally and socially. Our way of thinking about people ethically is wrong obscure and tribal. I am of the opinion Ellon needs to spend a 1 million dollar minute to think about phytoplankton and shrimp on our social ecosystem to get a true sustainable solution to the challenges that take him to a very well justified depressive state.
He says he is optimistic but I don't buy it I certainly am not! A whole new form of thinking about Humanity has to come up in order to maximize our survival common project of this little candle of consciousness in the vastness of eternal darkness. Anyway since I am not an advocate for free will whatever will come to pass will come to pass...
Ellon needs a good Philosopher, a really good one, an holistic thinker and that is really hard to get by. I am not convinced his tech friends smart as they might be are it...understanding concepts deeply to understand maths, to understand economy, to understand tech...
Finally I will make a prediction which is not hard to phantom...we have less then 20 years before a massive schizophrenic depressive epidemic is upon us and will drive us to double down on stupid action...we are already on the thick of it without being aware on the extension of the problem. You cannot win Mars before winning Earth first!
Disclaimer: This take is not anti meritocratic nor anti Darwinian regarding our social ecosystem, the nuance is to chose how narrow domain we want on competition in a global connected world with hyper competition such to balance the form we compete and induce innovation without driving the base of the ecosystem mad impaired and unproductive Neo-Darwinism cooperation on complex tasks has a word in this. And yes they have a role just like shrimps do...Don't be fool enough to believe "small people" don't have a role in the ecosystem.