No big name behind it
The .41AE did not have a big, influential backer. When S&W introduced the .40 S&W, it came with a large company, with extensive support and sales.
If it had been introduced by S&W, SIG or even GLOCK, it might have been a winner, but the introduction of the .40 S&W spelled the end of it.
Also, there was some negative comments on the case design. It has a rebated head, that is when the base of the case is of a smaller diameter than the body of the case.
The idea was that you would not have to change slides to convert calibers. Just springs and magazines. The breech and extractor would remain the same.
Some writers have writen that this kind of case head can be sheared off more easily by the extractor.
I have not heard of it happening, but then their has been little written about the .41AE for quite a while.
Jim