A factor of ten at $10K of income is wildly significant.
A factor of ten at $10M of income probably makes zero difference in behavior.
I probably shouldn't have said that comparing $100,000 to $1 million is equivalent to comparing $10,000 to $100,000. Yes, they're both an order of magnitude, but you're right that each subsequent factor of 10 jump in income probably matters less.
However, I still think you're nuts for suggesting that households with $100,000 incomes and those with $1 million incomes are comparable in any meaningful way.
And I still think you're channeling Mitt Romney.