I'm inclined to agree. A friend of mine turned down an invitation for them to go en famille to France for the wedding of a close friend's daughter, to be held in a chateau. Once they'd factored in air fares, hotel costs, a present etc., it would have cost them over £1,000. To be fair, the mother of the bride pointed out to her daughter that for such a wedding, she should be prepared that some invitees will turn the invitation down due to the travel and expense involved.
I also remember going to a wedding, both 2nd time a rounders, close friend of my husbands, again well over a 100 miles away. This involved a very nice sit down lunch, then back to the hotel we'd booked, out again for an evening do with practically the whole village in a marquee, seemed like an enoromous hoo ha to me particularly when they had a few grown up children between them. I'd have rather stayed in the hotel than go and stand around with drink in hand for the evening do, if we'd have had to drive a long way just for that part only, not sure we'd have bothered either. I agree with you OP, if people are travelling a distance, a sit down meal at least.