[Picture: Background: 6 piece pie style colour split with beige and woodland green alternating. Foreground: a head-on photo of a disgruntled looking white sheep. Top text: “”It’s love, we weremeant for each other”” Bottom text: “No, society has constructed normative boundaries so you ended up with someone similar in status to yourself”]
This is actually pretty true. It leads to a phenomenon termed the “marriage-market mismatch" where those who grew up in lower-income families to have low marriage rates even when they reach a point in their socioeconomic status where they can adequately support a family. The idea is that people will more often than not prefer to marry those from their same inborn background - class, social standing, etc.
Even if the income is still the same, to those in the elite group where the money’s always been there, it would still be “marrying down.” There’s a culture that even a college degree can’t breach for those from a more underprivileged background.
On the other hand, most people who do end up making it to the top are less inclined to marry those from the socioeconomic class they pulled themselves out of. It would be “marrying down” for them as well.
So conclusion is. According to today, it’s still new money < old money.