Why don't amplifier Companies use high end fuses?


My equipment - Raven Integrated Reflection MK2 tube amp 58wpc. / Lumin A-1 DAC Streamer / Synology NAS / Isotex Aquarius Power Conditioner / Furutech Rhodium Plug / Sonus Faber Amati Homage Tradition speakers.  

I have read thousands of comments on upgraded fuses improving the performance of sound.  I am very open minded but not sold either way.  So, the question I have is....if fuses were so important, than why don't Amplifier companies all install them as OEM equipment?  To me, if they are as good as people say, that would provide companies who use them a competitive advantage?  

Every High End Audio store I go to in Phoenix have told me it does not make a difference and is a waste of money.  For the record, I have fuses purchased at an automotive store for under $10 and I think my sound is awesome.  The Company that built my amp tested the Synergistic Fuses and he emphatically said there was no difference.  

If I were to try a fuse for fun, given my equipment, what would your recommendation be to try?  
willgolf
A test, for anyone who is interested. Take a 1 1/2 inch piece of painters tape ( I use the blue Scotch 3M 1 inch width size roll ), cut this piece the long way, to get yourself a 1/2 inch wide strip, and apply it on the glass of the fuse, leaving a bit of the glass showing on each end of the fuse, and put the fuse back. Of course, make sure the equipment is off, when you are doing this, clean the ends of the fuse of fingerprints, reinsert the fuse, and listen. Keep in mind, the equipment needs to warm up ( restabilize ). Do 1 fuse at a time. Can do this on any fuse. Let me know what you hear ? And yes, I am a tweaker. 
Maybe, just maybe, keep the fuse in the same direction as before removing it.
What exactly is that snake oil supposed to do aside from not even being possible in my F5 or risking jamming the fuse?
If ya don’t know I ain’t goin’ to tell ya. It’s for me to know and you to find out.