The $1m isn't in cash... You forget that the average house price in London is around $900k, and for Sydney it's $981k.

That means your pool for your car, furnishings, investments etc. are either minimal, or you have a mortgage, and definitely can't live passively off $30-40k per year unless you're living in cheaper than average housing (one would call this "not super wealthy") and definitely not if you're supporting a family.

I'm not saying the cost of living isn't worse in the US, just that $1m is a comparatively tiny amount everywhere and that most millionaires (as there will a correlation between net worth and frequency) are frankly closer to the working class than they are to billionaires.