And we know in fact that rhythm can act as a focus for attention. 2 for working memory, it should have been able to comprehend the longest possible Greek period. Someone wrote me privately about the very long rhythms of classical Indian ragas, which also seem to violate the limit of working memory. Anne raises the question of whether a stanza has some theoretical limit on the number of words or phrases. I would rather consider a possible limit on lines or periods.
Stanzas connected internally by rhyme can be very long without breaking apart or becoming bloated.
It holds together quite nicely and is perhaps the most intricate structure ever devised by an English poet. On the whole, I suspect that a regular stanza much over 20 rhymed lines would not work. If one accepts the colometry of Gentili for Pindar, rather than the modern Boeckhian lineation, then his stanzas can be pretty long. Personally, I'm increasingly sympathetic to Gentili's view, heretical as that may be. That sympathy is partly based on a recent translation I did of Pythian 4 using his colometry.