Mmm, very good point. Perhaps (as you suggest) the bonus structure isn't intended as an incentive to work harder/better.

But it does seem like a poor method to retain people... I feel like my bonus growing over time wouldn't be much of a motivator to stay if the work wasn't keeping me super interested, and my base salary wasn't growing enough to remain competitive. Maybe that's just a bias of mine, though, not to consider the bonus as a top criterion? Dunno.