Loudspeakers have we really made that much progress since the 1930s?

Has an understanding of the physics involved in making a loudspeaker gone anywhere in the past 80 years? Of course it has. Ideal is a goal.

Colorations, resonances, compression, high harmonic and IM distortion, … BAD- not ideal. 

Consideration of driver integration, radiation pattern, power scaling, low distortion, preservation of dynamics, … GOOD- closer to ideal.  

"Computers; have we made any progress since the 1930's?" Duh.
It's a New World.

One size won't fit all, I know.  
But if you are going to build an airplane you should know that you want to fly. 

Wrong. If you are going to build an airplane you should know that you want to crash in style.

[...] I wish that there were more current makers that are interested in the old-school sound that I like, other than the few makers of ultra expensive and massive systems like those using ALE, Cogent and Goto drivers.

Exactly my thought as well; a more widespread merger between old school design/sound and new(er) technology, so to see these older designs (or what's inspired by them) brought back to life with componentry and construction bang up to date, newer developed horn geometries, etc.

Obviously you know the answer, but are having a bit of fun.  Of course sound quality has regressed, if the goal is for the sound to be more reminiscent of real music.  

Speakers are, for the most part, smaller.  But there have been big tradeoffs in efficiency, dynamics, distortion, and ease of the sound.  We are left with poorer speakers that have to work harder and that make larger amps work harder.  That all equals worse sound.  It all makes no sense until you consider the lack of room some folks have and the wife acceptance factor.  Course, most folks could fit larger speakers and they could grow a set so they could negotiate with their wives.  

I carefully wade into this discussion by disclaiming, up front, that I am not very technical when it comes to field of high end audio. However, I'm hooked. I feel like I know "good" sound when I hear it but more importantly I know what sounds "good" to me. I've been into audio my whole life and only in recent years have I had the opportunity to settle for fewer compromises in my system. 

About a a year ago I had the opportunity to purchase a pair of Zellaton Concert speakers. I had heard these speakers set up at a friend's house and fell in love with their open, layered presentation of music. I'm not saying they're the best speakers on the planet, but for my ears and my budget they are pretty close. 

But, I say that to say this: the patent for the Zellaton driver was filed in 1930! I assume that the design is fundamentally the same and I know that each driver is still painstakingly made by hand. While I'm sure that the technology involved with the cabinet design, crossovers, etc. has changed, fundamentally this may support the case for a slower advancement over the years. 

http://www.audioarts.co/zellaton/pdf/patent.pdf