Sorry to burst your skeptical bubbles, but we had a savings rate of $10k+ / month, for many years.
Whose bubble are you bursting? I didn't see anyone claiming it was impossible to increase wealth at that rate with a very high savings rate, I just saw some skepticism about the numbers in this particular blog.
This dude has a graph showing the delta between (assuming gross) income and expenses, he was never earning anywhere close to $10k per month much less saving it.