It used to be that if you broke the male end of a fastex buckle, a not entirely uncommon occurrence, the only metric you needed to worry about when finding a replacement was size.  All buckles, be they 1″ or 3/4″, looked like the leftmost pictured below.  One buckle, or part of a buckle, reliably worked with another.

This is no longer the case.  None of the buckles above interface with each other, even the ones which look all but identical.  And this is a quick sample from my spares collection.  Go into REI with a pair of scissors and you’d have a hard time harvesting buckles from any two different brand which matched.  At all.  Do companies have really good customer service, and promptly mail a proprietary buckle for free at customer request?  I have no doubt some do, but am even more certain you can’t buy replacements for most proprietary buckles anywhere.  Given that these fancy designs have no practical value, this is unfortunate.  I imagine most of use would rather see R&D dollars go into better packs than integrating the company logo into zipper fobs (as a very nice Lowe Alpine pack I wore today does).  Of course, in this game of curb appeal few companies can risk not participating.