Your scenario of a buyer agent showing 30 houses over the course a month and not getting paid doesn't justify high fees either. (remonline.com)
There are some funds that charge substantially higher - than - average fees and justify the higher fees by pointing to the fund's performance. (investopedia.com)
I tend to agree with you in that more experienced agents can more easily justify higher fees, at least they should be able to do so. (remonline.com)