On an unrelated note, the Overpopulation wikipedia page is interesting: https://en.wikipedia.org/wiki/Overpopulation
We need renewable farming as well as renewable energy, and I don’t see any guarantee that such a thing can support a world of 8+ billion people.
All of the things you listed can be made renewable on timescales exceeding the natural lifetime of the sun with only engineering (rather than scientific) breakthroughs, including making the sun last longer and moving the earth to a different orbit to suit the light of the engineered sun.
No, Malthus gets the last laugh because the sub-population that reproduces most, regardless of whether that is caused by genes or memes, quickly dominates the overall population; this means that even despite the currently sub-replacement birth rate, it's reasonable to forecast the population to rise to whatever level is necessary to overwhelm food supply, for any level of food supply.
That can be fixed in principle, but the only solutions I can think of requires tech that makes the two forms of social/mind control in Westworld seasons 3 and 4 look like a child's finger painting in comparison to the filmography of the aforementioned show.
Only, we can't do that by just dismissing any discussion of the current problems — the best way to have a catastrophe is to ignore all the problems.
Every unsustainable behaviour works, right up until the point that it doesn't.
At least Elon is considering moving beyond that 'finite planet' limitation. But the way things are going, I suspect that modern civilisation will collapse well before we get there on any significant scale.
The limitations of Earth are basically about size of arable land, amount of clean water, lack of toxins in environment and the climate (percentage of areas where it's not too cold/hot for humans to survive outside). Other planets are terrible in all of those aspects and inhabiting them does not make sense (if we can solve these problems there, we can also solve them on Earth, but much cheaper/easier). They are hostile barren rocks that make places like Death Valley or Antarctica look like paradise on earrth.
They will probably be happy and fulfilled so long as you keep up the illusion.
You mean, the guy who pumps out private cars with years and years of massive government subsidies?
... but actually, looking at the prices, it seems like Tesla cars are super-expensive, meaning that only rich people will buy them, meaning that they don't even "contribute to electrification", they just contribute to rich people's ego.