which had crossed over from the merely excessive to the truly obscene

[Coffee Break]

I read this expression, "which had crossed over from the merely excessive to the truly obscene", but am finding it difficult to understand it. Could you please let me know what it means? Here is the excerpt:

I thought, I knew they were doing well, but I didn’t realize they were doing this well. And I wasn’t surprised they hadn’t invited anyone over yet, Lotte nervously explained that the house wasn’t finished, she said they would have a housewarming party as soon as they had fully moved in, and then suddenly added something about buying the house because it had such a good space for entertaining, they would be able to host fund-raisers and charity events. I nodded, they were clearly embarrassed by the incontrovertible evidence of their wealth, which had crossed over from the merely excessive to the truly obscene, without any of us really noticing.

- Katie Kitamura, Intimacies, Chapter 12

This is a novel published in 2021 in the United States of America. The protagonist is an interpreter working at the International Criminal Court at The Hague. Now she is at a house party hosted by her friend Eline and her brother Anton. So Anton is telling a story about the time he went to his friends' housewarming party, as to how his friends had such a luxurious house.

In this part, I wonder what is "crossed over," and what it has become.
Would it be "the evidence" that has crossed over? Or "their wealth"...?

If the former is the case, what would it mean that the evidence was first "excessive" and then became "obscene"...? (If I am right in understanding "cross over" means "to switch/become B from A", that is.)

 

[SoothingDave]

It's about their wealth. Their wealth had changed from being "excessive" to being "obscene."

 

[Amigos4]

When I hear "obscene amount of money" I immediately think of dialogue from the film Pretty Woman. One of my favorite scenes from the film can be found here. The specific reference to an obscene amount of money begins at 0:50.

 

[Coffee Break]

@SoothingDave and @Amigos4,

Thank you very much for the explanations and the link!
Wow, I grasped the idea of "obscene" money all thanks to you.

Then, it would mean that, their wealth had changed (=crossed over) from being excessive to being really obscene.
"Obscene" here would probably mean "ridiculously luxurious" or "aggressively/offensively rich". It might mean that their wealth was at such a ridiculous, excessive level that it might cause frowns from people.

As for "without any of us really noticing," I guess "us" does not include "them (the rich couple)"; they became very rich without any of their friends truly noticing their development in terms of their wealth.

I sincerely appreciate your help.

 

[Tarheel]

@Coffee Break You might be putting too much into that. The expression is probably meant humorously.