I understand that you might have been given it so far, but that is just a way stake thanked you, and if they are giving less now, that's mainly because they have more people to give and inactive ones were the first ones to go because of that, they have to pay active ones first without making a loss.
Very much the right way to understand the whole thing, first, like you pointed out, it makes no sense to create or make scene out of something we all consider to be free money, i believe no body is wagering for the sole purpose of losing so that they can collect a bonus by the end of the week or month, every one of us wagering are doing so expecting to win some big money in the process, the lucky ones among us still make that profit, and at the end of the day still get some bonus, while who are not lucky still get the bonus as a form of compensation, it is still stakes decision to do this, if they stop, customers who will be playing there will still be playing regardless.