So I can't speak to the actual motivation for the moon, but can for one reason for at-least-temporary human habitation there. Solar system exploration (and, inevitably resource extraction.

When you launch rockets from Earth, a vast majority of the fuel you start with is burnt off just getting to orbit, out of the deepest part of our gravity well. If you want to go anywhere else in our solar system, you're severely limited to what's left. The moon's gravity is low enough that it could work as a refuelling station. Provided we find enough water there and set up solar hydrolysis stations there and build the infrastructure to get it up to orbiting ships. All that will take people to set up, and possibly to manage long term.

In the case of musk and his billionaire friends, they just want to escape the consequences of their actions and become above the law. Basically they want to be a king, with no laws restraining them.

NASA spending has historically created more in return than is spent. It's somewhat expensive (essentially a rounding error next to military spending though), but the science done gives a good return on investment. This isn't just like on moon rocks or whatever, but developing technology that the missions need. Things like thermally reflective lightweight fabric, or a ton of other things. The science done on the Moon is worth a lot on its own, but it's also not the only thing we're getting out of it.

However, what are billionaires getting out of it? Hopefully it's just the opportunity to profit from the contracts and not something more nefarious. We all know it is though eventually.

There is enough material wealth in the asteroid belt to create a sustainable post-scarcity civilization. We could move out, and turn this little blue-green planet into a fucking nature preserve.

Settlements on multiple worlds within the solar system offer protection against risks that might otherwise end with the extinction of Homo Sapiens.

For the ultra rich - moving off world to escape the collapse of the biosphere is ridiculous.

Easier to "settle" the deserts of Utah of the Australian Outback than Mars - plenty of O2 and no worries about ambient radiation, but a very similar environment...

The moon is a great starting point to explore the rest of the solar system, doubly so if we found water on it.

I’ll quote JFK (probably more Ted Sorensen) on this one « we don’t do this things because they are easy but because they are hard […] »

The idealistic answer: Science! Lots of things to learn by establishing humanity's first extraterrestrial presence on our closest celestial neighbor.

The realistic answer: Capitalism. Lots of money to be made in mining the moon.

Epstein planet

I'd separate this into two different things - what is good for humanity and what is good for billionaires like Musk.

For humanity, venturing out into the solar system will advance science, and also help drive technological advancement which does have benefits for society as a whole. The space race in the 20th century did advance technology, and much of the modern technology we take for granted has routes in the space race.

But also humanity needs to move away from our current capitalistic system and that is very much driven by scarcity. The resource wealth in the solar system is mind bogglingly vast and if we can tap into even a portion of it, it could allow us to change how we as a species live. It would initially be driven by capitalism for sure, but when you have effectively infinite resources for a civilization, that changes everything we do.

Also for the long term survival of our species we need to be looking outwards. Earth is vulnerable - one asteroid strike and out species could be wiped out. Even if only a small number of people were to head out into the stars, it would help guarantee a long term future and resilience for our species.

I think one big mistake people make is that what happens on earth is a zero-sum game: i.e. for some to win, it must be at the cost of others. That is wrong and is a result of our terribly broken economic system. But we can both colonize the moon and mars AND fix the problems on Earth. And it may do good for our species to look up to the stars and have a bigger shared goal than just existing on this rock and acquiring wealth.

In terms of why the moon & mars. The moon is essential as a staging post for future expansion, as it's very expensive resource and energy wise to launch from Earths gravity well, but much cheaper to build at the moon and launce from there without the added step & complexity in design for launching off Earths surface. Mars meanwhile is the most viable candidate at present for a self sustaining colony long term (with a couple of moons of Jupiter and Saturn other options, and possibly venus as a long stretch).

Meanwhile, Musk is a deranged billionaire idiot. He is nothing more than a investor gambler; other people are doing the hard work making things happen while he is a public face of various companies. He really is peripheral to this, even if he does push the topic into the public consciousness. Don't conflate the idea of expanding into the solar system with that idiot. The idea precedes him and will run long beyond his life and any influence he has. He is just a narcissistic loud mouth with money.

Staging area for interplanetary exploration. It takes a lot of energy to leave the earth, making the rest of the journey to Mars or Jupiter quite difficult. It doesn't take nearly as much energy to launch from the moon though.

lot of big 'ifs' involved: re: the moon specifically -

if we can find water, we can make fuel and oxygen, instead of lifting both out of earth's gravity well. this could unlock a gigantic generation of probe exploration for much cheaper launch costs. and perhaps even human habitation, and later, human travel to mars etc.

mars - I don't see any good reasons to rush humans to mars, it would be a stunt at best. the distances involved and the amount of resources they'd have to schlep are daunting with current technologies.

so maybe a reason to start robotic exploration of the moon, specifically lunar lava tubes for potential habitation and shaded craters where water ice might be recoverable.

none of it should take our priority off of stopping climate collapse tho. let's keep the only space ship we've got habitable first.

Ask investors for more money

Next question