What does 418 trillion measure, though? The "wealth" of all human progress to the point of measurement?

If that's the case, then it's a measure of not just what goods and services are available, but what goods and services individuals in a global economy would be capable of causing. So, what could be done, given free markets rallying around that standard of measurement. This becomes even more abstract when you consider that as free markets grow, the abstraction in concern is one of those things that can be "caused". Bitcoin, itself, hasn't be priced into Bitcoin. That is to say, 418 trillion assumes certain existing infrastructures and markets for transferring goods. Since those have problems with efficiencies and Bitcoin improves about them, as Bitcoin improves, so the "418" value increases. This feedback loop is what some people refer to as "hyperbitcoinization," I think. But, regardless, as far as purchasing power, it's hard to measure purchasing power when you don't even know all the things you can purchase! It will only get harder to measure this for a long time, I think.

There are lots of fun caveats worth taking seriously, too, those are the problems we talk about in Bitcoin. Like the fee market, dangerously reliant on the subsidy right now (though we have plenty of time). But I'm more interested in sci-fi level problems--> The speed of light and interplanetary economies, see: #16368