To the casual observer there are not many differences in bicycles either. Both are technological devices, and bicycles still look rather the same (save recumbent types), still use gears, handle bars, etc. But they perform vastly differently.
I would assert that to the casual observer speakers have not changed much, but indeed they have, and they perform quite differently as well. Changes have occurred in cabinet materials and design (including isolation of individual drivers), driver materials, surround materials, magnet sizes and types, etc. - speaking only of dynamic speakers here.
Ngjockey, You are absolutely right that drivers have shrunk in size. This is one of the biggest tragedies of modern speakers. There is NO replacing cone surface area when it comes to performance. Make the magnet as big as you want; No way on earth these puny 6" drivers will ever compare to an authentic 12" driver when it comes to reproducing bass. There is a discernable difference in the quality of the low end between smaller woofers and the ease of a larger driver. The push to crowd the HT market with skinny speakers has wreaked havoc on hi-fi sound. Sadly, it seems most audiophiles do not even realize how bad the situation is. It's authentically hard to find a true full range speaker that's affordable.
Shrinkage of the midrange is another travesty. Again, there is a HUGE amount of difference in quality between a 3-4" mid and a 7" midrange. The larger driver sounds vastly different. Smaller midranges may be tonally correct, but I have heard many which simply cannot convey the correct spatial clues of the voice because they are physically too small. It's similar to the performance of a 4 cylinder car's engine versus the 6 cylinder. Both can do 65mph, but HOW they do it is vastly different.
So, yes, I can certainly see how someone who hears modern speakers which can only go to 40Hz and the performers sound like they're miniature would prefer the good old speakers. But when speakers today are made to be actually full range, with sizable drivers which can actually reproduce the full spectrum of frequencies - only then is one hearing what the best of modern speaker design can do. Add to it quality 7" or larger mids and you have some superb speakers.
And, yes, my Legacy Audio Focus HD's have these features. I did the review on them and happily purchased them because they have these qualities which are missing in so many speakers today.
It is absolutely apalling the number of dinky speakers on the market. To obtain anything approaching a full range experience one has to try matching subwoofers, which introduces problems to the sound. Audiophiles wonder why the high end is not catching on with younger people as much as they'd like. So, this younger person goes to a specialty audio shop and hears a speaker with 6" drivers three feet tall? Their CAR audio system sounds better than that! Give 'em monstrous speakers which are truly full range, speakers which will shock them with the scale and power of audiophile sound and maybe they'll be impressed enough to want it. But they can't afford the $10k+ that's charged for most of those speakers; not many people can.
So many audiophiles are convinced that they have the greatest sound with speaker systems that don't even cover the entire frequency. At least the older speakers with 12" or 15" drivers brought some bass. That's likely one reason that they are still enjoyed, because they actually were full range.
Once you hear what a serious floor standing full range speaker can do, one that can get down to 20Hz and below, and has truly full midrange, you realize how the other contemporary designs are "cut off at the knees".