Let me get this straight. You are advocating a fixed fee for mentchlechkeit? Perhaps I should ask my Rav if I can start charging old ladies when I help them across the street?
If a professional shadchan decides to hang his/her shingle and declare these are my fees, including handling charges for shidduchim that require X number of phone calls, or last X number of dates or require X amount of time, then go for it. Whoever utilizes this shadchan has by default accepted those terms. Those who dont like terms, will go elsewhere. Period.