Surgeries are not products that you purchase packaged in boxes and wrapped plastic at a store. Products are manufactured in a standard way and each individual item (except for machine errors) is pretty much the same. Product safety laws and testing typically ensures that what you buy is generally safe unless you misuse the product.
A results of a surgery can vary from one day to the next due to a whole host of factors and variables, none of which the patient can control. The list of these considerations is far too long to list here. While we would like to think of medicine providing a standardized product that can be duplicated indefinitely that is simply just not the case.
Before surgery you give your consent and sign wavers acknowledging that you understand there are no guarantees with respect to outcome. Mistakes and negative outcomes happen everywhere all the time. As with buying a car, the patient needs to consider their circumstances, their needs and their expectations and compare those with what is on offer at hospitals here in the DR and those in their home country where medical insurance coverage, patient's rights and the standard of care and oversight may be more robust.
You can choose to obtain a Lada or a Lexus. Both do the same thing but what you end up with is vastly different. Sometimes, the only visible difference is piece of mind and confidence in the doctor/hospital. With everything else being equal, lots of people see value in that piece of mind and given a choice, would lean in that direction.
The reality is that facilities, equipment and surgeon competency is not equal everywhere. It is not uncommon to hear of procedures done here needing to be redone elsewhere.