I think comparing the human body to a motor is perhaps not an accurate way of looking at things.
The human body is incredibly complex and there can be so many reasons pregnancy doesn't eventuate - unlike a car which has limited causes for a motor breaking down.

I'm sorry you've had such a horrible time with the clinics you've been to. IVF is never good. And sometimes I'm not sure if the staff of those clinics know they can have such an impact on people - even down to the receptionists.

I agree with you that IVF is certainly a money making business. But I don't think that is all they are. And I don't think a clinic would compromise your chances of success in order to have you come back for a repeat procedures.

I hope you find success in your journey and I'm sorry it has bought you frustration.