It's not that capital here doesn't exist - it's just concentrated to a toxic degree. Warren Buffett is a smart investor, but he can't squeeze the most out of every dollar, not at the scale he's obligated to invest at. Scale - especially the bespoke, "too big to fail" kind - invites waste.
Capital requirements in the US are also higher. In Uganda, people can become significantly wealthier and improve their standard of living simply by having a few chickens. But in the US, individuals are taking on debt just to have enough education to get a job! And the level of spending needed to operate in most US industries is similar to the costs of college education. Like you point out, software is exceptional in this respect since it has an extremely low capex - so we can conclude that, in fact, individuals are capital starved in the US as well.
Capital requirements in the US are also higher. In Uganda, people can become significantly wealthier and improve their standard of living simply by having a few chickens. But in the US, individuals are taking on debt just to have enough education to get a job! And the level of spending needed to operate in most US industries is similar to the costs of college education. Like you point out, software is exceptional in this respect since it has an extremely low capex - so we can conclude that, in fact, individuals are capital starved in the US as well.