Can't let the middle-class get too uppity with things like financial security, now can we?
$140k in any number of US cities is solidly middle class. That's also the point where you can't contribute at all.
The contribution scales to zero linearly with AGI from 125k to 140k. And we're talking about a $6,000 contribution here, which is nothing compared to the $19,500 you can put into an employer plan.
And that's per wage earner, so double if you are dual income. (A huge implied tax on active parenthood)
But anyway, if you have that much to save, after 401k and 529, you above almost all the middle class, whose total household income is below your savings.