You can already listen to 24 bit music for decades. You don't need true 24 bit resolution for that. You can't hear -120 dB signals in music anyway (if it could be recorded in real life situations anyway).
It's not like you could ever hear the difference between -120dB and -140dB distortion and noise anyway.
The improvements are only technical improvements by chip manufacturers and designers making improvements on the borders of what's technically possible.
There's been a lot of replies to this, but I figured I'd reply to the start, since they are all generally agreeing with this point (that I could tell).
I will have to respectfully disagree with the implication that all this climb to extreme fidelity has no value.
Specifically, the presumption in the above statements are that the audio range you're using when you talk about "-120db" is matched so that the maximum represents the human maximum hearing. That is almost
never the case in real audio chains.
Historically, before I got wise to the issue of matching dynamic ranges to the effective ranges of the audio hardware I was using, there were times (I found out later) where I had been giving up on the order of 65-70 db or so of the upper part of the range due to my enjoyment of listening to quiet music (gain in various audio stages, powerful amps, sensitive speakers, the maximum range of the music being played, etc.), and got lackluster results accordingly. So a device with say even 100db+ of dynamic range might end up only with ~35db or so left above the noise floor before hitting the absolute bottom, and other distortions that typically happen when you get near the bottom of the operating range. I'd had it happen both with DACs and with even pure analog preamps.
In summary, while I will agree that for recordings, 16-ish bits/44.1khz is plenty (given it was recorded to set the proper dynamic range for human hearing), the problem is that when your DAC outputs it, matching the effective range either requires manual matching (like using passive resistors or a very good high dynamic range analog preamp), or you end up giving up digital active range due to unused headroom.
That's why I think so many random people claim that the newer crazy-accurate DACs "sound noticeably better", it's that they often have sloppy audio setups where those dynamic ranges are not carefully managed.
Anyway, I'm happy with the progress that's been made, as it brings high fidelity even to the audio-chain-lazy masses!