BPT you are arguing on halacha. Look at the Rama who discusses when a shidduch breaks up before a chassuna. In many situations the shadchan did their role and deserves their compensation(of course if the breakup was becasue of the shadchans deliberate misrepresentation of the situations then they are the cause and a mazik.) Halacha compares a shadchan to a broker. If they close the deal they did their job. If you buy a house please don’t blame the agent if you break a leg next week on the front steps or if you have bad mazal in your new home….
There is no artificial price tag. it’s simply what each communities minhag is to pay.
Perhaps you are confuing a shadchans role with the role of parents schools etc. it is not the shadcahns role to ensure a happy marriage.
The shadchans role is to set up the singles to the best of their ability. certailnly if a shadchan is dishonest etc then they are simply not doing what they pretend to be doing. But it is not the shadchans job to make sure the boy is a mentsch or the girl knows how to be a wife and mother.
Please don’t blame a shadchan for the shortcomings in what parents etc shold be doing..
Either way i think this argument is once again going in circles so hatzlacha…