I guess a 8-core Xeon W costs a cool $1K by itself, 10Gb networking isn’t tremendously expensive these days so it probably contributes $300 to the cost at MSRP. Still, $6K is too much, $4-5K would be less outrageous and still turn a healthy markup.

Yeah, I was expecting it to be either significantly more powerful than the iMac Pro or to have a lower cost for the base model. Neither of those things happened. I was willing to go out of my way to get hardware that's not quite ideal for my use case and still pay extra for it just to have macOS, but $6k is just too much. It might be expandable but each generation of Intel CPUs is incompatible with the last generations motherboards. If you care about single-core performance then it just doesn't make sense.