Sound quality of Newer versus Older speakers


From a sound quality perspective, is there anything that newer speakers are doing better than older speakers. For reference, I have a pair of Monitor Audio Silver 300s which are amazing me with their ability to balance detail retrieval with an ability to avoid harshness (with the right ancillaries). My subjective perception is that this type of balance between resolution and refinement was more difficult to find in speakers from 20-30 years ago.
calvinandhobbes
There are lots of good loudspeakers today. But large statement loudspeakers from years ago can still produce great sound if they have not deteriorated over time. 
The Quad 57 (designed in '55) is still the benchmark for "natural" sound! Every audiophile should own a pair or two. I have two pairs for stacking!
I guess that the biggest overall change across all of the brands has been in cabinet design and refinement, aiming to minimize energy storage, and keep them quiet. 
Good older speakers are just fine and usually represent excellent value. Really very little has changed in speaker design.