As a Protestant myself, I can tell you that you're grossly mistaken. It isn't about wealth. It's about Jesus Christ. Therefore, I'll ask again: why would any Christian envy the wealth of the Catholic church, when that is not what matters?
"Leftists, too."
Ah, so you group non-Catholics with leftists. Revealing, that.
" But the wealth is just an excuse. It's bus fare on the world scale. The main envy is of the Vatican's stature as an institution whose message can't be ignored, after being written off so many times in 2000 years."
Your priorities are in error; they cloud your thinking. It's not about your denomination, nor your church, nor your traditions, nor your "institution." It's about the Lord Jesus Christ, who gave His life so that we could live eternally with Him.
Anyone who comes to Him, Catholic or not, receives that grace and that gift. Yet you think folks are worried about the Vatican's treasures.
Wow.
"But you knew that."
What I know is that you seem to have a problem with misplaced pride. Remember the Scriptures---and there are a few---which instruct us to boast about nothing but the Lord.
. . . which was clear from your being touchy about hearing someone define envy, when you're obviously familiar with the word as a speaker of English. It's something Catholics do, even if everyone knows the everyday meaning of a word, to re-discover it anew by looking through the eyes of a Doctor of the Church like St. Thomas. Protestant scholars do it primarily with Biblical quotations. Denominations, like tribes, have their customs.
Catherine of Aragon was a brilliant and heroic woman—arguably a martyr for the sanctity of marriage, since Henry VIII kept her a prisoner in poor, unhealthy conditions that killed her pretty quickly after he took up with Anne Boleyn. Catherine was supported in her defense of her marriage to Henry, and the indissolubility of marriage in general, by a great many leading lights of that period, including Martin Luther. Of course, Luther went to his grave considering himself a Catholic. (For that matter, so did Henry.)
I would not be shocked if Catherine (Catalina) were canonized one day. She seems to have been selfless, holy, courageous, and clear-sighted in her grasp of what was at stake. You have chosen an excellent nom-de-plume—and perhaps an intercessor worth praying to.
Please note that I went to some pains to point out that I don't think the Catholic Church's wealth is the real reason for envy on the part of most Protestants, or indeed, Leftists. I think it's the Catholic Church's claim to having been established by Our Lord Himself, and for being the most reliable source of the truth. So yes, indeed—the Church makes a bold claim, and it's about Christ.
May God bless you in your every discernment.