Here is my 2 cents on the topic:

- If we are talking about lugged lightweight steel bikes, I'd say that after the introduction of index shifting, not many things have changed. That said, current steel tubing is better than that in the 80s, but not necessarily lugged. Also, the addition of brifters and 10 or 11 gears in the back is a mechanical progress
- Aluminum bikes, which used to be the top of the line and demand very high prices in the 80s, have been manufactured most cost efficiently and are thought as below steel (other than boat anchors) bikes these days. In other words, the $199 X-Mart aluminum frame mountain bike would have cost about 5 times that much in the 80s.
- Carbon has been improved a lot both in strength and in originality of designs as a frame material
- Personal aesthetics and preferences are just that: personal; which means that there is not a "right" or a "wrong" answer. I personally enjoy lugged steel bikes and prefer the ride of a steel bike over that of an aluminum of CF bike, but I think that a lot of people out there are happier today because they can ride aluminum mountain bikes with suspension all over.

And, yes, bikes do evolve. Whether a particular era was the "peak", methinks we are about 200 years or so away from answering this question... subjectively