I once drove 2 1/2 hours at night out of state just to wish someone mazal tov. This was financially and time wise a great strain and I did not harbour any ill feelings that I was not invited to the whole wedding or that I could not hitch a ride and I would never, ever have accepted payment for the trip.
I went at great expense because I really wanted to and I wanted to do so personally. I took a flask of coffee and some danishes for the ride there and back and to this day I am still warmly thanked by the family.
We have had many family weddings all over the world and some of us travel and some don’t or can’t. I would be horrified at having to pay someone to come to one of my simchas. Weddings will always have their own simcha and freichlichkeit whether it is with local guys and girls or just a few out of towners.