I'm still over $25k in debt for Student Loans; in large part my own fault for being the type of personality that tends to at times splurge on "entertainment" items (like a new iphone) rather than saving up and paying off a big hunk. My wife on the flip side actually had been paying off her loans all throughout school and then massively afterwords and is now completely paid off. We both make roughly the same amount of money, but whlie mine is going to various debts her extra is going into a retirement fund.
I have a friend who makes less than me, however his father died (His mother died when he was much younger) and he inhereted the paid off house. He doens't have a mortgage payment and as such has a fair bit more disposable income than I do.
Going back to my wife and I. My wife would likely live somewhat like the lower class if given her druthers, even though she'd be making significantly more. She's hard pressed to splurge on "luxury" or "entertainment" type items, would be fine in a tiny small house or apartment, doesn't go on big trips or out to huge events most of the time. She's always got a fair bit of cash saved up due to it. On the flip side I'm the type that likes to spend the money I have to enjoy the things I want to enjoy because that's why I work. I typically have far less money immedietely on hand because of it but the appearance of my life style would be better because I have and am doing more stuff.
Its such an abstract concept that unfortunately has been so polarized and politicized as of late that its tried to be made into some solidified thing and it just doens't really work.
$150k for a family of 3 up here in NOVA could potentially be solid middle class. Back home in Roanoke VA it'd be upper middle class for that same family of 3, and wealthy if it was just a single person.