It would take me years of study to get to the point of building my own tube amp. That takes time and time and expertise is what you also pay for. Time is expensive and means a great deal to us humans. It has been said that to become an expert in any field takes at least 10,000 hours of study and time. 10,000 hours is a lot of money :-)
My tube preamp amp sells for $4000 and the parts including the case, tubes etc. cost far more than $400. Heck two capacitors in the unit cost $400 total!
I am also paying for the mind, ear and experience of the amp's designer. I love the sound of my preamp and it sounds far different and better to my ears then all other preamps I have heard. Are we wanting and willing to pay for this musical experience which is unique compared to other offerings?Yes, for me!
In addition to the parts, time, expertise, unique design and sound you are also paying for these real business costs;
- marketing
- building, tools, employees, benefits, insurance, all sorts of costs from utilities to toilet paper in the bathroom
- costs to travel, attend, set-up and work all the industry shows and events
What about the need to price with a sales profit. Yes profit. The builder needs profit as well as the retailer be it internet based or brick and mortar.
How many $4000 amps can really be sold today? This is not high volume business, so since the business model is not based on volume it must be based on high margin return. That is the business reality. If the builder is only going to sell 100 units, then they better make good money on each unit to pay all the costs listed above and make a living.
Seeing amps that sell for $4000 - $15,000 is certainly no surprise to me. It seems like a must based on the business model. Just attending the shows must carry an annual budget exceeding $50,000 for many.
Your question has many moving parts that must be considered to give this topic a full and realistic viewing.
As for SOTA attempts that sell for $50,000, well I can assure you that you won't ever be able to build these. The cost to market these and get to the shows required is very high indeed. If only a few dozen are sold, then the margins must be very, very high.