To me, this can be an evidence, that most of the even highly expensive DAC's cannot do true 24-bit! Just reminded about it.

Oh, no, the situation is even worse. Right now, there are just a few DAC chips that can reach true 22 bit analog resolution. Sure you can cram 24 or 32 bit in their interfaces, but those 'lower' bits will be just covered in noise and distortion until they reach the 20-22nd bit levels (counting from 'top').

In studio processing, sure, they can use a 64 bit path if they want, to cover all those manipulations and round-up errors. But this is digital domain, when you hit the ear, you still need and Digital-To-Analog module, because we hear analog signals only.

 

PS: For reference, 22 bit true resolution means a THD+N lower than -132dB, 21 bit means better than -126dB, 20 bit means better than -120dB. Compare that with your favorite DAC numbers.