In my mind 600k is past that point. It's rich.
I understand why you say 7 kids is a factor. It shouldn't be.
In my mind >200k is well to-do
When someone with 7 kids makes $60,000, he's got breaks for tuition and government help with rent, medical insurance, food, etc.
Once someone makes more than the income cutoff, he's paying out of pocket for all the things listed above, which has a value into the tens of thousands. Besides paying 30% in income taxes. So a person with $200,000 in income doesn't have a tremendous amount more to spend than the person with $60,000 in income.
So my cut off for comfortable is closer to $300,000.
$600,000 is nicely upper middle class.
Rich to me is being able to buy houses for your kids. That's much more.