If anyone here bought a handgun and found a defect...
I don't believe that's especially relevant to a discussion about wear/abuse.
Yes, if your knives were defective then it would be reasonable for them to reimburse any shipping/handling. Your knives aren't defective, they're just worn out and possibly abused. It's very unusual for any manufacturer to provide warranty repair for wear or abuse.
...they'd get in touch with the manufacturer and DEMAND they send a free pickup order for the gun, and expect it to be sent back to them free of charge, under warranty.
Given that there's no claim on your part that the knives are defective, there's also no warranty claim since there's no warranty for normal wear/abuse.
Victorinox AG guarantees all knives and tools to be of first class stainless steel and also guarantees a life time against any defects in material and workmanship (save for electronic components 2 years). Damage caused by normal wear and tear, misuse or abuse are not covered by this guarantee.
So it doesn't make sense for you to compare this to a warranty repair.
But the gun companies are held to a higher standard of customer service and expected to pay the expensive shipping costs both ways.
It's not a different standard of customer service, it's a different situation. They are expected to pay shipping both ways
in a warranty situation where they are remedying a defect. But that's not how anyone would reasonably expect a gun company to handle a situation where a customer sends them a worn out, broken gun and wants them to repair it.
It seems that the warranty is very useful for what it is intended to be useful for. It's only useless if one expects it to cover things it says it won't cover. Your complaint that the warranty is useless is similar to someone complaining that the jack that was provided with their vehicle was totally useless when they were stranded in the dark and needed a flashlight. Jacks are very useful for what they are intended to do--lift up cars so a wheel can be removed. They are only useless if someone expects them to do something for which they were never intended.