poorly mastered or recorded CDs still sound like dog poo but that is not the fault of the medium which has gotten much better over the past 35 years of its development.I don't think that the medium CD has done ANY development since it it were defined by Sony and Philips.
A fun fact is that they defined the CD and its specifications. Then the CD manufacturer needed to manufacture a CD that meet the specifications.
But the same went for the CD drive manufacturers they need to be able to read a CD that meet the specifications..
And someone needs to measure the CD that it meets the requirements/specifications. Otherwise the media and drive manufacturers would be in the dark..
But in the end a CD from early 80-ties will play fine in all CD readers if it meets the specifications. Same same no development but today we have better clocks and electronics. So that CD will sound better today than it did then..

