StationC:

Is going to a wedding, no matter how expensive the travel, a compulsive financial pact to toss material goods at the guests of honor?

No, but receiving an invitation to a wedding is.

I do understand and sympathize with your logic, but etiquette dictates that anyone receiving an invitation to a wedding should send a gift. It needn't be expensive, just thoughtful to the couple. Logic would also question why anyone who could afford the cost of a plane ticket (and perhaps hotel room, rental car, etc.) to attend said wedding could not also afford a gift.

Just out of curiosity, when you don't attend the wedding, do you send a gift that's commensurate with the amount you would have spent on airfare? Because I'm thinking you could get off cheaper by just not attending and sending a gift instead, if getting off cheaper is your goal.