I think I saw in another forum, can't remember which, this same topic. They were all comparing booking with a TA because they expected an on-board-credit for their booking. One even said if the agent did not give them, then he would not book with them.
I agree with all of you. When was the last time your local grocery store or WalMart, or furniture store, or clothing store. etc. gave you an in-store-credit everytime you book with them. If an agent gets 10%(?)of the base rate of a cruise that cost $800.00. How can that agent afford to give back part of her/his whopping $80.00 before expenses. Out of that $80.00 comes her salary, utilities, office expenses, etc. She may be left with a net profit of about $15.00, maybe. Do the math. I am figuring this on your local, small-town, store front agency. The big guys may be quite different, I do not know. But supporting your local businesses if a plus for everyone, or you may see more and more empty store fronts in your local town.
Just my opinion.