JWs like to think they have found the one true religion. But like so many other religious people, it's usually the religion they were born into, the only religion they know because it's the first one they found or, at the most, one of two or three (typically the second one after they left their first / born-in faith).
The trouble is, there simply isn't enough time to explore and investigate each and everyone of the many thousands of belief systems, religions and sects around the world.
Think of it this way: which is the best neighbourhood to live in where you would be most happy and most successful? Not just in the city or even the country you are in, but the entire world.
How would you ever know? It would take a year at least of living somewhere to really truly know what it was like and what all the people were like, more likely 3 or 4 at least.
Picking a branch of religion like Christianity or Islam maybe like choosing a country to live in (sometimes they go together). You can discount some and pick one but most often people are born into the place they are and that is the choice made for them.
But then the number of cities and neighbourhoods within a city are so many, the best you can do is pick one and be as happy and successful as you can there.
In your lifetime, if you changed every few years, you'd likely only ever have first-hand knowledge of maybe a dozen at most. And wasn't the purpose to find the best one to spend your life in? If you're moving about, you never really get to live in the best one you found because you spent so much time moving.
And yet some would have us believe that "God" expects us to find the right one and will kill anyone who doesn't. What a twat.