In the last 20-30 years, what has changed most...

I am curious, what has improved more in the last 20-30 years, amps or preamps?

Another way of asking would be, if you had to chose, would you rather have a 20-30 year old amp or pre amp?

It seems there are still some old amps that are holding value, but I rarely if ever hear about old preamps.

Just curious btw. I am not searching.