What makes a DAC so expensive?


You can buy a Cambridge Audio AXA25 25 Watt 2-Channel Integrated Stereo Amplifier | 3.5mm Input, USB Input for $225, and most DACs seem more costly. 

I'm wondering what it is that makes a Bifrost 2 almost as expensive as an Aegir and 3x's as expensive as the Cambridge product, above. I would have thought an Aegir would out-expense a Bifrost by a factor of two or three. What are the parts that make the difference? 

I'm wondering if the isolated DAC concept is one that comes with a "luxury" tax affixed. Can anyone explain what I'm getting in a Bifrost 2, or other similar product that justifies the expense...?

Thank you.
listening99
I own both the DirectStream and the Ares ll and find the PS significantly better, though the Denafrips is an amazing bargain...that last 10% often costs a lot...on the other hand, I could probably sell the PS and take less of a loss than on the Ares, so actual cost of ownership would be less...before PS started selling direct, their actual prices were way less than list...
Just get an RME ADI-2,  Topping D90,  Benchmark DAC3, and forget it. DACs are to the point of transparency, they can be made to have sound signatures using the nonsense mentioned above but in the real world a DAC converts digital to analog without adding or taking it should be neutral. If you wish to add distortion use tubes. A $99 Schiit Modius would be indistinguishable from a $60,000 MSB to pretty much anyone since amplifiers and speakers have more distortion and noise than even inexpensive well engineered DACs. 
I will add you might be able to tell the PS Audio garbage from other DACs they measure like crap. 
@djones51

see we woke up on the wrong side of the bed this morning

sorry that being on this lil forum makes you so unhappy