To put a billionaire in perspective, it's more interesting to think about the income than the capital. You can get a 5% annual return from some fairly low-risk investments (and you can further reduce risk by spreading your money across a load of these). You can often get higher, but 5% is a fairly good baseline.

If you start with $1bn and do nothing clever, you can get an income of $50 M per year by doing nothing. Even with the kind of 95% tax rate that we had for the highest income levels when The Beatles sang about it, that leaves you with $2.5M/year in income.

That's enough to buy a nice house every year, with no mortgage. It's a disposable income of almost $7K. It's enough to take a first-class transatlantic flight every day.

And that's just one billion.

Even with a 95% tax rate on investment income and a conservative investment strategy, someone with a billion dollars would have a daily disposable income that's more than the monthly income of anyone in the bottom 99% of earners, without having to work.

Now try these calculations again with real tax rates and Musk or Bezos' wealth.