I think the dose and how long the medication is taken for are important factors when it comes to amitriptyline effectiveness.
A low dose amitriptyline is usually enough for neuropahty related symptoms. My doctor started me on a low dose and increased it slowly over months until I was comfortable. Some people take too high of a dose too quickly and experience side effects and quit the drug too soon. This is bad because it takes a while for amitriptyline to really work.
I think if used properly and in the right doses, amitriptyline can be very helpful for neuropathy. The responsibility really falls on doctors to make sure that their patients are using the medication correctly and for long enough.