Well the basic question here is something like "how do we maximise material comfort?". The answer is pretty obvious - machines. Humans haven't changed much in t

Well the basic question here is something like "how do we maximise material comfort?". The answer is pretty obvious - machines. Humans haven't changed much in the last million-odd years, all the improvements since around year 0 AD have been improvements in what machines (ie, capital) we build. We had a long period where the people with highest social status were war-leaders and we chose them without much care (often a hereditary aristocracy). That led to pretty grim outcomes. It turns out if we award highest status to the people who own and deploy capital efficiently we get absurd amounts of capital produced and this frankly ridiculous society where a tiny group of really driven men seem to just build everything. So yes, capital is important because we declared it to be so, but we declared it to be so because the society with more capital wins wars. Sometimes by driving over the opposition in that capital, gotta respect a good tank charge. More capital is just better, and capitalism is the system that is most effective at encouraging people to build more capital.