@firearm12 has got it. My understanding almost matches with the above. Playing music is not same as copying a file from one directory to another or from one machine to another. It also inolves time domain which people keep forgetting. Copying hard disk is bit perfect. It doesn't matter if the file copy happened in 1 second or 1.1 seconds. After the copy you will get the same file as the original.
Music playback is very different. Let us for the moment forget about the sampling rate and assume that after delta sigma conversion we got a perfect representation of the original signal. So let us just consider that we are going to play music which has been perfectly copied to a wav, flac, dsd file. Now for the point of simplicity let us assume that the music is a 50Hz tone. This means for the music to be perfect, a sine wave has to alternate between plus and minus exectly 50 times in exactly 1 second. You Play the 50 Hz in 1.1 second, you just lowered the frequency. You play the 50 Hz in 0.9 second, you have increased the frequency. Because of the noise and also an imperfect clock, any dac will nevery be able to play 50 Hz exactly continuously. To achieve perfect playback, an insane amount of engineering goes into the dac to engineer at minimum the below
1. Very high quality clocks
2. Very stable oscillators based on the above clocks. These oscillators are affected by noise and power supply
3. Extremely stable power supplies using large caps, super caps and low drop out voltage regulators
4. Insane amount of shielding
5. R&D for delta signma algorithms.
Things which where so easy in a LP player (because of heavy platter making it difficult to alter the RPM suddenly, stable mains frequency, etc) now involves better engineering, better components to excel the sound that came from a decent LP player.