Speaker Technology over the last 10 years

IMO you have to answer that by comparing advances across speakers at equivalent price points then and now. I think designers have a very good picture of frequency response and depending on the sound they are going for will be forever tweaking driver placement in all three dimensions and crossovers, not much new there. If there is one area where speaker technology continues to advance is in the materials. Treatment of the drivers -B&W using kevlar and Monitor Audio with its gold tweeters, cabinets being made out of new composite materials and improved feet/spikes all looking to remove unwanted resonance. The added benefit of new materials is that most decent quality speakers today will likely last much longer than say speakers from the 70-80's with their degrading foam around woofers, cracking butyl rubber and cabinet vibration that occurred as some types of glues/adhesives aged.

Speakers are always dependent on the source. Always. Garbage in, garbage out.

But that said, speakers have the greatest difference in sound from design to design and design is a moving target. Driver design has changed some and I think there are drivers available now that were not in the early 90's but that deoesn't mean that there weren't some excellent speakers available then which are still excellent speakers, by any standards, today. Subsequent speaker refinement has been incremental, not earth shaking. FWIW, my favorite speakers were designed in 2004 and possessed a quality in both resolution AND frequency response that did not previously exist (at least I had not heard, or heard about).

Bottom line, if you still love to listen to your Legacy's be happy! If you are not happy, there are lots of viable alternatives.

I think most of the advances are at the micro improvement level in speaker technology. The bigger improvements have been in playback technology, both analog and digital.

A good pair of Klipschhorns, Martin Logans, Tannoys, Magnepans, Quads, Paradigms, B & W, Vandersteens, they still sound stellar.

IMHO.