Ah but here's where we run into a problem - what would be corruption when excluding wealth? (Though in fairness I was talking about material gain - wealth being a part of it, so are things like small things, lands, etc. tangible physical things) I don't see for example how corruption would manifest in terms of social status, unless you mean blackmail, gaslighting, etc. for the sake of becoming famous (though the question there is also - does the notion of fame too change over time? I'd argue that this is still within my framework of corruption since the component of power and fame that is a big aspect in it is material access - within a post-scarcicity system that might change, but we also don't know how such a society would look like in practice, we can merely speculate at this point in time).
A teacher that gave a student better marks in return for sexual favours is corruption. A politician suppressing an investigation of an ally's misconduct (or starting a bogus investigation to damage an enemy) is corruption. And so on.
I think if we're going to argue that the end result of any form of success is some degree of material benefit, well okay. On the other hand, I think that's quite reductionist and doesn't necessarily cater to real motivations. Lots of people cheat at online games, but they don't earn anything from it: they get a buzz from feeling superior, or admired (even if it's fake). Some people will take positions in society not because the positions pay that well, but because it allows them to exercise power over others, and so on.
The thing is though as well, is that ideologically, it is largely justifiable under capitalism that personal gain in the abstract is beneficial for society as a whole. A billionaire, regardless of their mode of income, will still spend money and stimulate the economy, consequently create a need for jobs and capital circulation that can result in growth and prosperity for all those involved in this chain of expenditure.
I am not sure that is true. Economists have suggested many forms of income generation that can be harmful. Rent, for instance, is often a way for the uncreative and unproductive to extract wealth from people who are creative and productive, and who could achieve much more if they didn't have the dead hand of rent sucking their resources away. If people are pouring their incomes into assets like housing, chances are it's less productive than pouring their assets into business investment.
Also, I think capitalism is often misrepresented. To read Adam Smith is to see the basic argument that self-interest drives attainment, but also to see a huge number of caveats and concerns. He notes, for instance, that people have a tendency to over-admire the wealthy and feel disgust for the poor in ways they don't deserve. There's discussion of the risks of wealth and power imbalance, and morality.
I think discussion of capitalism is twisted because the capitalists have the greatest power to expound a message and control society, and they tend to be amoral, self-interested and self-regarding. Of course they tell us that they're totally awesome because they are rich, and the richer we let them be the better it is for everyone. It's in their self-interest to do so. And of course they are less likely to admit all the downsides of letting them become stupendously rich. For instance, executive pay magnified hugely in the 1980s on the basis of academic research which suggested increased pay motivated better output. Obviously, the executive class decided this meant if they gave themselves huge sums of money, their companies would do better. Interestingly, however, academic research had also produced a load of research suggesting no link between increased pay and performance. But if you're a self-interested executive, it's terribly convenient to select the research that defends you handing yourself a massive bonus rather and ignore the research that doesn't. Similarly, why did this principle not filter down to the lower ranks? Why do the executives get motivated to better work with massive pay increases, but the grunts apparently aren't?
It's all power, really. Corruption is also enabled by power. Hence why societies need to empower systems to squash it.
But here's the thing - personal gain is also mediated heavily by social factors...
Impatience? It's more difficult than impatience. Let's imagine a country enacts a huge program to combat corruption, and refuses to develop in the interim because the investment may spur corruption. 20 years go by. But that's twenty years it's fallen behind in development. It's people are probably less educated, with worse public services, worse healthcare, poorer jobs, etc. This is a lot to ask of a population, to see themselves fall behind their neighbours. For its population that crave jobs, advancement, security and wealth to see it there ready to be used, but be denied because a paternalistic government decides it's bad for them until they're ready. I fear that government isn't going to last long.
There's also the idea of threat. When European nations colonised Africa, African tribes either fought each other to get slaves to sell to Europeans, or they didn't and fell behind the tribes that did: but faling behind endangered them - risked them being dominated, driven from their land. Nations today still have their insecurities and worries of being dominated by their neighbours. Wealth is power, power is wealth.