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

No one has suggested that there has been no progress since 1930s.  The BIG deal is that very good sound is now affordable and practical.  The stuff from the 1930's, 1940's and 1950's that deliver good sound were meant for theaters and would not fit in any normal living room and was extremely expensive given wages at that time.  Even theaters could not afford the Western Electric systems and most of these were leased.

There is no doubt that, given advancements in technology and knowledge, it would be possible to make similar sounding gear that is better.  There are companies that intend to do just that--make gear that sounds like old Western Electric, Lansing, Klanghorn, etc. gear--but actually improve on performance (e.g., ALE, Cogent, Goto).  There are current manufacturers that attempt to make close replicas of such gear (e.g., Line Magnetic and G.I.P. Laboratories).  Whether any such gear is actually "better" is purely a subjective judgment.  In any case, the sound of these followers of old school sound is quite different from mainstream gear and it is pointless to argue which sound is "better."  If you like that sound there really hasn't been that much progress, and it is largely an academic exercise arguing that advanced technology "could" make that kind of sound better because there are so few companies working in that area. 

Have all of those who have been arguing that modern gear MUST be superior actually heard a Shearer system or a system with a WE 15A horn or any of the other 1930's contenders? 

I just looked up the links that you provided, johnk.

I have no problem at all with people listening to speakers from the 30s and saying that they prefer that sound above all other.

I simply disagreed with what you appear to believe, that there has been little or no progress in speaker technology since the 30s and that we should all own 30s speakers. Sorry, but I still think you’re wrong.

I think that speaker technology has improved significantly since the 30s and that everyone should listen to as many speakers as they can and buy the one that works best for them. That can be homemade speakers, speakers from the 30s, huge speakers, tiny monitors made in the 90s, the most recent Wilsons or Magnepans, Bose speakers, whatever one prefers.

I don’t even have a problem with people listening to speakers they don’t really like but they have to own because they can’t afford what they really want or their significant other won’t let them bring what they really want into the house.

So johnk, Enjoy your vintage speakers and believe in your heart that they are the best speakers in the world with my blessings. But if you try to tell me that they are the best speakers for me or that there has been no real advancement in speaker technology since the 30s, I will disagree.