Why do you think hair transplants are falling in popularity?
There is always a growing demand for it, especially for countries such as Turkey where this kind of tourism is booming. Unfortunately, this means many new clinics with no known reputation and greedy unethical clinics are coming out of the woodwork with fake reviews on forums everywhere (many here too, so if you see one report it ASAP), which makes getting it done in Turkey a bit of a landmine. As far as I'm concerned, anyone who goes out of their way to fake reviews is unlikely to have an ethical practice, so they are the ones to avoid.
In this day and age, it is easy to research into the 'big three' as well as various options such as micro scalp pigmentation/concealing products/hair systems, so it's not surprising that people are considering those options too, but as far as I can see, there is still a growing demand for hair transplant.
You just have to look at the 'new research and technologies' section of this forum and it becomes apparent that none of these 'promising' technologies are anywhere near, and the few recent findings which seemed to have potential (sandalore, Brotzu lotion, RU etc) all turned out to be barely capable of maintaining, or at best producing vellus hair that will never turn terminal for most cases. Hair transplants are here to stay.