Some WG's like to perpetuate this idea but it's false and an act of conditioning. It's actually something I particularly dislike because lies like these take a long time to prise out of a fluffy's head.
Just because you can turn people down doesn't mean you control anything other than who you will see. That's not power over clients that's power over yourself. On the grand scale of things nobody else loses out except you. The money that would have gone to you just goes to someone else and the punter still gets his jollies off regardless. With the greatest respect there is nothing special about any WG, there will always be younger\older, sexier, prettier, curvier or better skilled WG's for a punter to choose from.
The choice a punter has is absolutely staggering and you really can't appreciate this fact until you see punting through our eyes. The 'power' as you call it lies in the hands of those willing to part money for sex and there is A LOT of sex on offer. In reality if WG's had the 'power' then you wouldn't be in competition with each other. There would be no adverts, no profiles, no touring, no price wars, no undercutting. They'd be no agencies, no fake ratings, no bitching and definately no incessant whining about lack of work.
In fact if you truely had the power you wouldn't even need to advertise. Men would wait their turn patiently for an opportunity to be with you and when they finally got their chance they would lavishly spoil you with money and gifts in the hope of seeing you again...like true Courtesans. But it's not like that is it? Punters are not in competition with each other. There is no waiting list, no mad scramble to book someone and definately no fighting over WG's. There is plenty of sex to go round umpteen times and not for ridiculous amounts of money either..
Add all that up then take into consideration who is constantly selling and who is casually buying and you might get a little closer to the truth to where this 'power' actually lies.
The above might have some validity as far as parlours and flats full of ever rotating EEs who are there to extract the maximum cash with the minimum of effort in the shortest time. Of course they are going to compete and moan when they don't get the punt. There are plenty of us who avoid such venues.
There are other wgs out there, hard though it may be for you to believe, who don't operate on a conveyor belt system, who have the privilege of filtering their clients via email and so have the power to choose. If your email her "3pm, OWO, full sex, CIM, rimming" she probably won't bother to reply. You may think "well I'll take my money elsewhere, stupid bitch". To which she would reply " thank God".