Just needs a little time. It wasn't that long ago when only a few people had Twitter and FB accounts. IG even took a while to gain main stream traction.

Plus unfortunately Musk is fairly well known for underpaying his staff. So you have to choose to take a paycut to switch from Google / Facebook. To be fair all of Apple/Amazon/Microsoft do at least sell actual products.

Perhaps this is why Google / Facebook open source so much of what they do, so that talented engineers don't just have to say 'I get paid to make people click'.

"It's kinda sad that social media and advertising is the most lucrative businesses and so many bright minds work on that instead of for example ..."

So, how would you employ the engineers instead?

Industrial society is about producing garbage for the masses to consume. The huge churn of capital and labor creates as it's byproducts from time to time items of actual human value.

But those things would be fragile and complicated without the industrial economy surrounding them. If we look at this stage in our species history from far away, currently the industrial economy is supposed to be predictable and mundane.

So, "producing useless crap" is a required feature of our economy so it can occasionally produce science, art, medicine and the other things that actually improve us as a species.

Now, consumer goods fall into two categories: physical and digital. Physical consumer society is turning our biosphere to shit. Digital commodities, on the other hand, are much more lenient on the environment.

So, if we look at it this way, and presume that producing consumer crap is necessary for economic growth and stability, it's much better to work in producing digital goods and services rather than physical ones.

Within this framework, the actual question is not why do the brightest minds work at facebooks, but, will our economy ever develop beyond the point where producing useless crap is not so much a necessity for systemic stability rather than an occasional indulgence.

That's because the only real monetization on the internet is advertising, and ecommerce (which relies heavily on advertising).

Pretty much every consumer website on the internet deals with one of those areas. If it becomes easier to movie money on the internet, we might start seeing new dominating players other than Google (ads), Facebook (ads) and Amazon (ecommerce).

A generation or two ago all the brightest minds in the world were working on ways to kill the most people as efficiently as possible.

This is progress.

It's not actually sad. Social media and advertising involve incredibly complex and vast search spaces. The problem domains are massive and solving the issues in those fields, like scaling software and hardware, enables us to build tooling and infrastructure that every field can use. So those businesses are the bootstrapper for other businesses. Example: SpaceX wouldn't exist if Paypal didn't exist first.

"Who thought the future would be giant chemical rockets (100x BFR?)thundering around the solar system?"

It's not. The math doesn't work, the rocket equation bites too hard. This is one of the reasons to be keeping an eye on the recent claims over the past few years that fusion reactors may be something that could be shrunk down to shipping container sizes in the relatively near future. Get a functioning fusion reactor into space and suddenly the solar system is, if not your backyard, something very reachable.

But it's possible we won't see any practical way to lift off from Earth other than chemical rockets for a while.

Once we have a real space industry I imagine there will be progress in areas like ion propulsion. You'll still need chemical rockets with >1 thrust/weight ratio to get off planetary bodies, but ion propulsion could be much better for long haul trips.