I'm not sure what direction you were hoping for. Can you explain?
If I choose to do more, it's because I connected with the couple and made a conscious decision to give more than what they are paying for. If I don't get thanked for that, I feel I gave them a freebie.
Reality check here : if you didn't get paid more money then you
did give them a freebie, thanks or no thanks. If some one promised to thank me endlessly I'd still want paying for shooting their wedding. Thanks doesn't pay the bills, does send your daughter to college etc.
If you aren't happy with your situation, change it. Set up your own company and see how little thanks you get from the employees who think they are paid too little while your customers think you are charging too much, all while you are having to cover costs that most employees have no concept of.
So, getting back to your opening post, exactly what were you hoping we'd come up with to make you happier?