I have really tried to find an explanation for this since I came across your question. I read some 130 pages in From the Clarinet d’Amour to the Contra Bass
A History of Large Size Clarinets, 1740–1860 by Albert R. Rice, but it covers periods only up to late 19th century.
Some Google searching found 2 threads (one mentions the other which mentions Rice's book - small world) bringing up your point: here and here.
I resorted to ask Rice myself; it took him less than 2 hours to reply.
Thank you for the interesting inquiry concerning clarinets.
It is my understanding that Russian clarinetists were playing German-made bass clarinets during the first half of the 20th century when Shostakovitch and Prokofiev wrote their bass clarinet parts. Both of these
composers knew the woodwinds played by professional Russian players and they would have written their low Ds and Cs because they were available on the instruments. The Heckel Company in Biebrich is
known to have exported their woodwinds all over the world, and their 1906 catalog indicates that they offered bass clarinets in C, Bb, or A with a low E, Eb, or D.
He continues with the alto clarinet,
Their alto clarinets were offered in F or Eb with
a lowest note of E. However, other German makers such as Kruspe in Erfurt offered alto clarinets with low Eb keys. In addition, the Zimmermann Company was established in 1875 in St. Petersburg by Julius Heinrich Zimmermann,
who by 1905 had factories in Leipzig and Moscow where woodwinds were very likely produced.
And gives sources for more information,
More can be found on Heckel instruments in the latest issue of the AMIS Newsletter where a review by James Kopp discusses two recent books on the Heckel firm on pages 22-24.
On the soprano clarinet,
The use of a soprano Boehm-system clarinet with a low Eb key was quite popular in Italy and Spain during the 19th and into the 20th century. Italian players like the full-Boehm system clarinet because they preferred transposing A clarinet parts and playing them one instrument. As a result many makers of German and Boehm-system clarinets offered an optional low Eb key.
I guess these models reached Russia through German makers in this case too.
As for the first composers and pieces to use the extended range, he writes:
There are histories of the clarinet during the 19th and early 20th centuries written in Russian. If you are close to the New York Public Library or the Library of Congress, you find them and photocopy the sections, then have them translated to determine who were the earliest composers in Russia to use the extended range.
Albert R. Rice
What a champion this guy is, send him his well-earned reputation points :)
The chain of events as I see it is: extended range clarinets were made available to Russia --> players bought them --> composers were aware of this and wrote for them. This is in contrast to cases where composers request (demand?) instruments which players then need to get.
I can only assume, myself, that Western players and composers were more familiar with the French models which, to my knowledge, didn't reach the extended range but had advantages in tone quality, sound production, intonation, fingering etc.
I can reply to him if you need additional information or clarification.
Michael, I think that you are rather close to NY. If you want to copy those sections he mentions I can take care of the translation.