But then there are those in this thread arguing that Elon Musk's reward should be unlimited because he's "arguably ensuring the long-term survivability of our species." Wow, that sounds very important. I guess he should have the most money then.
Nevermind the fact that the majority of his wealth is literally gained by "sitting in a chair and taking cash". That's the job of a capitalist after all - they don't work for their money, they sit in a chair and let the ownership of assets make them money. I mean, sure he's "doing things" but are the things he's doing worth $140 billion? What has he "done" in the last 9 months that made him $88 billion richer? Is the planet saved yet?
The return on investment is the payment it is in our self-interest to give for this activity, because we want and need such work to be done (so that we can make use of the fruits of such ventures, instead of getting nothing at all when wealth is squandered on bad ideas or just plain old consumption).
Why not give a billion to a random business owner to come up with what to do?
Certainly, if you think you can identify people who are particularly qualified to pick good ideas and make investments in them, it's not a bad idea to give them some money (but where do you get that money? hopefully not somewhere with negative externalities such as stealing it from different random business owners). Although structurally it's better if the billion itself is given as an investment instead of a gift, because then the person giving the billion has "skin in the game" themselves. Which is basically what I think VCs do, although I don't know how effective they usually are.
(Yes, this whole thing assumes a regulatory framework where businesses that have negative externalities or are otherwise bad for the world do not make profit. Indeed, companies that use dark patterns or rent seeking tactics to make profit should be legally punished, and if such punishments make them bad investments it's a good thing, because it means they were on net bad for the world.)
No one benefits by the mere "existence" of SpaceX/Tesla. People benefit only from what those companies produce, and the things those companies produce only come into this world by way of people selling their labor to design, engineer, and manufacture the rockets/cars. We can go all the way down the supply chain and say that people only benefit from Tesla due to the people mining lithium in other countries. And yet the CEO of Tesla believes that the people mining his lithium deserve to have their government replaced by a US-backed coup to be more friendly to his corporation.
The point isn't that we should "seize profits". The point is that the guy at the top isn't producing as much value as he thinks he is compared to everyone below him. They are producing the real value, they should be getting the wealth. Maybe Musk still comes out of the equation the richest one of them all. Fine. But he doesn't have to come out a demi-god with more money than he could spend in 100 lifetimes. There's no reason that needs to happen.
There are things that make people more efficient as a homo sapiens and we want them to enjoy those things and not to worry and stress various annoyances so they can concentrate on what they are best at.
But as you say it's obviously not like that for CEOs of big companies. Just because Bill Gates was good at selling software doesn't mean he should hold this immense power in the world and decide how to allocate resources between vaccines and cancer research etc. It has nothing to do with his meritocratic expertise (of course he pays his own experts, but he does maintain the high level control). Some would argue that this value was all created as additional value by him via the efficiencies enabled by the software and that it wasn't merely captured out of existing value. It's obviously a combination, but based on ideology people estimate it differently. We know that rent seeking and dark pattern business practices exist, as do lobbying and other forms of corruption.
The billionaire examples aren't examples of meritocracy but of rewarding luck. Nobody would say that as a human Elon Musk is literally that much more competent than, say, the best senior engineer at Tesla.
But also, beyond a certain point rich people aren't people any more, more like institutions. They just channel that wealth in different directions, they cannot "enjoy" a significant potion of it as a human being. All that money gets rotated back into salaries of others, else it would remain just numbers in databases. It cannot meaningfully accumulate. Just like if you burn a bag of cash, you induce minuscule inflation effects and everybody else's money increases in value a little bit. If a billionaire sits on his cash, it's as if he didn't have it. But when he uses it, he pays salaries and makes people do stuff. The problem is when this stuff is "the wrong thing".
I think the main argument against billionaire power is that the distributed wisdom of crowds and markets are better at allocation and deciding what's worth doing than centralizing it without limit. It's good to centralize it as long as it's about merit and related to expertise or capacity, but not beyond that. Billionaires are way beyond human scale regarding that.
There are real and difficult things to do in the world that some other people need. They (employers, clients, customers) decide that this work is so important to them that they exchange money for it.
Then the person can use that earned money to improve their life.
For example if a top surgeon flies to a different country to do a difficult operation, I'd want them to be able to enjoy a relaxing VIP lounge, bigger legroom and direct taxi. Rather than flying low cost and standing in the bus for 3 times longer than the taxi ride.
We want to allocate resources to people who accomplish important things for us. Not just as reward or motivation, but in our own interest, we invest in the most capable and competent to have more of our stuff taken care of.
Jobs aren't just about sitting in a chair and taking cash and we just pick who gets to sit in which chair to enjoy that cash. It's doing things. And we want those things to be done well.
This is the idea behind meritocracy. Not that we praise people for their genetics.
I'm not saying this is how it works currently, just that this is what we mean by meritocracy that we should move toward.