The mass production of neodymium magnets has allowed some worthwhile improvements in driver design.
Borresen Acoustics has done some interesting work in lowering the inductance of its bass/mid unit through the elimination of iron.
That's just two examples of "under the surface" progress in loudspeaker design.
The Manger and MBL drive units are innovative.
In general audio is no different to most other industries in that the majority of progress comes from incremental improvement. The internal combustion engine is a good example - most of the conceptual work was done in the early twentieth century - lead by aircraft engines. However, advances in electronics, materials science and precision engineering have allowed significant improvements in performance, fuel economy, emissions control and durability. Even the electrification of cars is only taking a well established core technology.