Why manufactures don´t burn in their amps and ...

"this hobby is so subjective that when you have 2 audiophiles in a room, you will get three opinions."

That's nonsense. You will get four opinions.

This I believe: components don't burn in; listeners burn in. "Burn in" is a metaphorical cousin of "break-in": baseball gloves require breaking in; conert grands--specifically, the action-- require breaking in. The wood in string instruments changes. We love to think of things breaking-in, balancing, aging into maturity and ripeness. We like to think of metal components, non-organic and w/ no moving parts (excluding drivers), doing the same. Isn't it odd, though, that "burning-in" is supposed to result in better sound? Isnt' that very congenial on the metal's part? Why should that be? We imagine things "limbering up," "getting settled." Just as I like to imagine that my tube amps give me a warmer, more open sound. I suspect that I'm transforming the literal warmth--the visible glow--of the tubes, and the delightful, illuminated open space inside the glass globes themselves, into my perception of the sound. Solid state. I mean who wants to hear music from something called Solid State. Definitely not open, and not warm and glowy.