War and Peace

The mid-20th Century saw the end of a long period of cataloging and counting.  Not that counting has ended, but it's no longer sufficient to just go count how many monkeys are on that island. 

Back in those days, there was a cultural category for "maximum" things including big novel, and longest word in the dictionary (antidisestablishmentarianism) later replaced by Broadway's supercallifragilisticexpialidocius (sp?). 

W&P, rightly or wrongly, was typecast (again, a Categorization and Counting-era concept) as the Longest Novel.  Joyce's Ulysses got the nod for most inscrutable Long Novel.

Should a longer novel have been read or written since then, W&P would remain in its slot because we simply don't think about literature in that way anymore.  Popular music is a C&C dinosaur in that it still operates in the old way. Once a (typically dreadful) tune becomes popular, it's permanently popular and one cannot escape hearing it repeatedly forever, at least whereever there are radios.

Which is why I stay home a lot.