I’d be glad to tell you my opinion if you’d specify for whom; a single person, a married couple, a family of 2 kids, a family of 6 kids. And where do they live?
“Decent” doesn’t really apply, you earn what you earn and if you want more you are free to work to earn more.
Sufficient is perhaps the word you mean? And if it is than there is no way to set it because 5 million isn’t sufficient for some (because of their inability to live within their means) and 50,000 is more than sufficient for others.
Personally, I’ve been all over between earning none to a high of $51,000 (as a couple) a couple of years back. I consider us lower middle class and we live in Indiana, by choice because it is cheaper here. I grew up in California and wouldn’t dream of living there now.