This is totally anecdotal, but then, so is most of this thread so far.
Regarding paying to go to High Holy Days services, at one point, I was seriously considering converting to Judaism (I didn’t, for reasons that I have no intention of going into here, but my experience was 100% positive.) During this period, I went to temple on one of the High Holidays, explained that I had no ticket, and asked if I might stay in the lobby and listen to the services. After waiting long enough to be sure that I would not be doing someone else out of a seat, the rabbi’s wife graciously invited me into the sanctuary. It was an altogether beautiful experience.
For what it’s worth, my understanding is that one of the reasons for temple memberships in general (as opposed to High Holiday tickets in particular) is that, since observant Jews are not permitted to engage in monetary transactions on the Sabbath, passing the plate as many Christian denominations do is not an option. Makes sense to me.
Brace yourself for rampant speculation to follow.
Regarding displays of wealth by Jews, my only contribution is based on both my general impression from going to Jewish museums, reading books, etc, and on a conversation which I had with a Jewish friend once. Essentially, since Jews from the Middle Ages on down were subject to harrassment, arrest, expulsion, etc. (for "etc., read “slaughter”) at a moment’s notice, (and perhaps because Jews in some places and some times were forbidden to own property), it was considered a good idea to keep assets in a portable form in case it became necessary to flee at a moment’s notice.
Although showing off wealth under those circumstances would have been a** truly **bad idea, keeping something handy to bribe people with in order to stay alive would certainly not have been. I can see where this might have evolved into a desire to accumulate gold or jewels (concentrated wealth in a portable form which was a universal medium of exchange). This habit could easily outlive its original purpose and, in a safer environment like the U.S., evolve into a tendency (among people who could afford it) to wear more jewelery than the average bear. What better way to celebrate your survival against the odds than to show what had previously been hidden?
I hope this interpretation is not offensive to anyone. It most certainly is not intended to be.
It would be interesting, as well, to know how diamond cutting evolved into a Jewish pursuit (as in N.Y.C.'s diamond district), and whether that has any bearing on the subject at hand.