Electronics are complicated. A great DAC is more than the sum of its parts. The rest of the chain is important too. That Tom's Hardware test is kind of crap as they only seem to be testing headphones and not speakers. Great DAC's are meant for very high quality speakers. They also don't really say how they are testing them. Are they just using the output of the headphone DAC? All great DAC's have separate outputs to the speakers and headphones. The headphone output is usually inferior to the speaker one. Great DAC's are also mostly only supposed to be DAC's, not headphone amplifiers.

Great implementation of how a DAC chip works coupled with detail to all other sections (ie. power supply) make a huge difference. This argument against a quality DAC is like saying the output of every car is the same if you only look at the fact they can get you to the same destination. Ridiculous. Talk to anyone who actually works building and designing these systems and they will laugh at you if you tell them its all the same.

Can you hear a difference? YES. Can you hear the difference if you listen to a $1000 DAC on your crappy logitech 2.1 computer stereo? NO. But that's not the DAC"S fault. Diminishing returns for sure, but 99.99% of the people saying their is no difference in sound do not have a signal chain to hear it. Put jet fuel into your car. Going to make your car run better or faster? NO.

Do most people need $1000 DAC's? Absolutely not. Are some companies producing mediocre products and charging huge prices? YES. Just like any other industry. Do your homework people, and if you have great studio monitors or top quality amplifers and speakers, then get a great DAC. But again DO YOUR HOMEWORK ON THE PRODUCT. Do you buy a car by going to the first lot you see and taking the first car you see no questions asked? Didn't think so.