Why is Debussy's remark brilliant (on going out and smoking, at the start of Beethoven's developments)?

Question

From: Charles Rosen. Critical Entertainments. p. 117 Bottom - 118 Top.

  In the same way, attacks on Beethoven could be profound and even persuasive, and would continue to be so after his death even to the present. Most musicians (outside of Central Europe) will appreciate the brilliance of Debussy's remark at a concert during a Beethoven symphony: “Ah, the development section is beginning; I can go out and smoke a cigarette.” The way Beethoven's reputation was “constructed” is perhaps revealed best in some comments made in 1812 by a close friend of Goethe, the composer Karl Friedrich Zelter:⁵
“I, too, regard him with terror ... His works seem to me like children whose father is a woman or whose mother is a man ... I know musical people who once found themselves alarmed, even indignant, on hearing his works and are now gripped by an enthusiasm for them like partisans of Greek love.”

A few years later Zelter was to become the teacher of Mendelssohn, who would take the latest and most difficult works of Beethoven as models for his own compositions, but in 1812 Beethoven was a monstrosity for Zelter.

1. Am I right to infer that Debussy judged these development sections boring and unworthy?

2. Even if yes, how's this judgement 'brilliant'? Isn't it churlish and cheeky?

Answer 1

In short, the German musical tradition (largely based upon Beethoven's towering presence) is one that prioritizes thematic development. Beethoven was known, for instances, for sometimes introducing and developing new themes in his codas!

This propensity for thematic development was not necessarily shared by the composers in the Italian and French traditions. This quote from Debussy would have been a quip against what he would have felt was an unnecessary fetishization of thematic development.

Some related quotes from Richard Taruskin's Music in the Nineteenth Century (The Oxford History of Western Music, Volume 3), pp. 21–22:

But the avoidance in [Rossini's] music, on the one hand, of rigorous motivic unfolding, and, on the other, of symbolic harmonic drama was something German musicians and their colonial adherents found infuriating, for these (along with the spirituality that was assumed to result from them) were the very terms on which they staked their claim to universality of appeal. . . . [W]hat was a lack in Rossini [of thematic development] was turned by later generations of "Latinate" composers into an avoidance, and touted. The best illustration is a quip supposedly made by Claude Debussy . . . while listening to a symphony by Johannes Brahms . . .

(No, that's not a typo; Taruskin claims this was at a Brahms concert, not Beethoven. But the rationale is still the same; Brahms's First Symphony, after all, was jokingly called Beethoven's Tenth.)

As for whether Debussy's remark was "brilliant" or "churlish and cheeky," that's ultimately a question of opinion and probably can't be definitively answered. My sense is that Rosen was probably using "brilliant" in the sense of "clever" or "funny."