I didn't really get the crux of your first paragraph. If I phrased it wrongly, then I apologize. But I thought I clarified it afterwards.
I don't think Im talking about something different than Merlin was.i just disagree with him.
To put it in kindergarten terms:
Merlin - more bookers means more relationships to keep good, yay
Me - more bookers means say "fuck em" (not literally ) to the asshole bookers. if I can book through other bookers, asshole bookers are dead to me
I don't believe in keeping good relationships with people who don't treat you well. And many to one relation means that you (not you in particular, but any monger) dont have to keep up the appearance of a good relationship while cussing them under your breath. You don't have to have thousands of faces or have fake courtesy or a fake smile. Hence my initial bootlicking comment. I understand the need to have a good relationship with an asshole if this asshole is the only entry point to something you want. When there are multiple entry points, maintaining good relationship with the asshole doesn't make sense to me.
if Merlin has been around for 15 years it's likely he has seen Cari and experienced her booker, for example. Let's just say that booker is not regarded highly by a lot of mongers. I'm sure if there was a way to book her with several near universally liked bookers, many would choose that way instead and just not engage with the asshole booker.
It seems we all agree that there are asshole bookers. We just don't agree with how we should go about them if there are alternatives for each such asshole booker.