Why don't amplifier Companies use high end fuses?

When I auditioned a pair of Odyssey Audio monoblocks, in my home, I had occasion to remove the covers(with Klaus’s permission). Apparently, Mr Bunge(electronic designer and manufacturer) believes fuses make a difference, given the amps had all the fuse holders(mains and rails) stuffed with HIFI Tuning’s products. Don’t know if he sells them equipped that way though.

That's what you're impressed with? Did you even read the specs on that stuff? I'm looking at the Stratos Mono. They claim 120 amp current delivery. Through 6.3 amp fuses? With a 400VA transformer? Not for very long if at all! To sustain the kind of current output would mean rail voltages sagging to 3.2V. He's calling it out as 180 watts into 8 ohm. That suggests he's running 32V secondaries off the transformer for rectified 40V rails. That figures out to 4.74 amp. To keep the 6.3 amp fuses from popping at 2 ohm means it'll only put 79 watts on the outputs. 

Here's the bottom line. That amp is built to a budget, most obviously. It couldn't have cost much more that $500-600 to build. It seems to me to be pretty ridiculous to spend 10-20% of the build budget on fuses when that same money would buy a much larger transformer which would make a vastly more meaningful difference. It's very likely that the fuses make a difference because that's the exact kind of anemic power supply that would be prone to minor perturbations. I know I've said this many times before. 

For comparison, my little home brew amp is 31wpc and has a 600VA toroidal with 24V secondaries for 32V DC and it will drive 300 watts into a 2 ohm load without a hiccup. 

Are we going "off the rails" here?🧐

No. I've contended many times that fuses might make a difference in amps with less than robust power supplies that are more prone to minor variations. It looks like rodman up there pointed to a great example of what I'm talking about.