24bit is irrelevant if you use a lossy format like MP3 or AAC. If you use raw PCM (WAV, AIF...) or lossless FLAC you may feel the difference in a very good sound system.
I have an entry level audiophile system and I can assure that a lot of the records hold a shitty sound the will not benefit with 24bits/192KHz.
Moreover, in my town there are almost no hi-fi sellers because everybody listens music in portable devices with dubious quality.
The way records are being made has changed since the beginning of the dominance of MP3. One of the consequences is that producers focus in strong bass and light high because in a compressed MP3 those are the most hitted freqs...
In a low end system if you reduce the sample rate to 32KHz (from 44KHz) you will not feel the difference and they talk of 24bits... This is pure BS.
In the 80's even with analog systems sound quality was almost the same as today.