They should charge more for it…

Price has become THE main feature, at the top-end of market. I mean, it’s been that way for a while - just more so now. Just make sure your product uses enough visible "material" to "justify" its price level - minimalist philosophy like Rega’s doesn’t fly in this market segment!!

When a well-heeled customer's wishlist starts with "I want the BEST", and it's a subjective pursuit, this is the inevitable result (women, wine too).

There is the concept of diminishing returns. Improvement at the high end becomes exponentially more expensive. To most mere mortals, the ability to discern improvement lays far below the mega dollar prices that much of the uber high end pieces proport to offer. 

Is a $250K turntable 10 times as good as a 25K table? Not by a long shot (IMHO) I don't play in that league so a moot point. I guess if you have Bezos or Musk money, go for all the gusto or bragging rights.

They are absolutely correct. If you think about it, anyone who could afford a $300k turntable can easily afford a $500k turntable. So maybe the manufacturer should have asked $500k for it. Why not? It would not make any less sense. If his audience is the billionaire class, we are talking about pennies for them. Money has become so highly concentrated that it’s hard to wrap your head around the meaning of wealthy anymore. There are around 800 billionaires in America alone. These products are not intended for regular working folks. Ponder this for a second: 1 billion is 1000 millions. 

I think Einstein was referring to a hypothesis, not to audio gear. A hypothesis should be as simple as possible to explain the data, but not simpler.

The design concept of the GMT is reminiscent of an older very high end turntable that was made in the Pacific Northwest and now may be out of production.  (I can see it in my mind's eye, but I cannot recall the name.) A very powerful 3-phase AC synchronous motor is driven by three separate and discrete amplifiers, one amp per phase and controlled by precise upstream circuitry to maintain stable speed without the need for a separate servo mechanism. The bling that you guys object to is not appealing to me, either, but the idea and its execution appear to be first rate. I like that part.

There is the concept of diminishing returns.

I don't buy into diminishing returns. That assumes solid objective evaluation criteria, and also paints the picture of a nice clean horizontal asymptote where performance NEVER decreases as price increases infinitely to the right. Reality is a LOT more random than that.