Truth. Chassis, OT, PT, choke and headhsell is well over $800.
Add the boards, faceplates, all the components, and then time to put it all together...
You'd need to charge a good amount of $ to make it worth the time.
That's just paint by numbers.
Doesn't account for the knowledge and skill that folks like Jeremy have, who tweak each amp for optimal performance and tone.
And then there's customer service.
Some builders are totally accessible, happy to talk, help with any issues, and even tweak an amp to fit your needs.
Others have no interest in talking to you, helping you with common issues like fuses or tubes, much less make adjustments to an amp.
Some take your $, become difficult to communicate with, take way longer to produce the item you paid for then was stated...and sometimes it never shows up at all.