Why have capacitors improved so much over the years?

I have not been involved in the engineering of any audio product but If I were, I would insure that that no corners were cut on the electronics. Unfortunately I think capacitors are generally the weak-link especially in Class A amps and any given product is only as good as its weakest link. If there were a way to eliminate capacitors, that would be miraculous.

Yes, Lou's post was very good & made for some interesting reading. I can't understand either why manufacturers go through all the trouble of designing a piece of gear & then at the most critical point insert cheap caps.