I think in terms of reliability and longevity, we've really refined the electrical engineering that goes into newer SS components, or I'd like to at least think that we have.

Doping materials for silicon is better now than it was 30+ years ago, transistors are smaller, run much cooler, and therefore last longer with a lower TDP, thus produce less strain on cables and connectors, and so on.

I think the major issue with modern components is that they're all surface mounted, which severely limits the repairability of some things, at the cost of being small, efficient, and inexpensive; but I think that fact is offset by the strides we've made in electronics since the early days of computing.