One of the big differences from 40 years ago and now is a dramatic drop in the noice floor and increasing differentiation of discrete sounds within the music. There are lots of other changes. But I think those are the two main ones.
I have followed the cutting edge (distantly at first… with a very low budget… but increasing over time) for the last fifty years. What is possible now at a relatively modest budget… and even more at a less modest budget is incredible.
If you were to upgrade to even a Bluesound streamer or better, inexpensive integrated amp, and some contemporary floor standing HiFi speakers (B&W, Dynaudio, Sonus Faber… etc), you would just fall over in awe of what audio can be today.