Also, because the 'alternative' is not that nice or attractive.
Believe me, I did in my youth try to walk away from this religion, but the awful behavior of non-JWs made me return to what I was accustomed; the "nothing is wrong as long as you're not harming anyone" attitudes and "anything goes/do not judge" way of life... I just couldn't handle it.
Ultimately, do not think I can today either. Here's is comfy and nice, so I'll stay, even with all my opposing views.
DY