They sound great too

but yeah, there's that. How often will you use a warranty on a decent amp? 3 years covers the period in which you are going to have an issue if it has a problem most likely. I can't recall an amp I had to have warrantied so far, except the Emotiva XPA-3 B-stock. It had a damaged binding post and they replaced it with a new unit. I sold the 3 and bought a 5 off a member here; that was at least 10 years ago.
You never need it until you do need it. Just because it hasn’t happened to you, it doesn’t mean it can’t happen to you. That’s just life. Sh!t can happen any given year. Just ask the people who actually needed repairs.
But warranty isn’t just about needing service. When an established company offers you a lot more warranty, it tells you they stand behind their products. They are putting their money where their mouth is. They are proving that their amps have such high quality that they can offer you 20 YR warranty. They’re not just SAYING WORDS. They are doing the deed.
But probably not everyone feels this way. Like I said, there are multiple factors. Not all factors are equally important to everyone. Some don’t care about warranty at all. Some people don’t care about aesthetics or pride of ownership at all.