Of course, most post-avantistes today consider the pentameter, along with everything else, broken a long time ago, and why not.

Pragmatics is a branch of contemporary linguistics; it emphasizes language as communicative utterance. One of the things it looks at are the pre-suppositions of a speaker regarding his or her audience, which influence all the choices of vocabulary & style. If you looked at the attitudes of various modern & contemporary poets toward style through the lens of pragmatics (as R.A. York did in The Poem as Utterance, back in the 80s), you could interpret the style of their "utterances" as motivated by social attitudes.

Why would a poet like Crane not break the pentameter, to take a salient instance? Perhaps because the social attitudes motivating wide ranges of modernist experiment - such as "epater le bourgeoisie" (then) or "disrupt oppressive social systems based on standardized syntax & meaning" (not too long ago) - held little value for him. The simplistic binary polemics which offer a bourgeois-sellout "them" vs. an aesthetic-political vanguard "us" are based on attitudes which severely warp the reception/absorption of the main stream of poetry in English; this has its consequences for practice.

A quote from R.A. York's The Poem As Utterance, a study of 19th & 20th cent. European poetry from the vantage of "pragmatics" - a branch of contemporary linguistics (Methuen, 1986). Speaking of the usefulness of same, he writes:

"it might lead to a soundly based classification of utterances, as, for example, between those which aim primarily to alter the world and those that aim primarily to effect a communion in appreciating or comprehending the world." (pp. 8-9)

Here we have another version of what Mandelstam called the future of poetic research : delving into the impulse of the text.

Look closely at this divide : doth it not faintly resemble the avant/quiet picture box?

O my peeps, there's something deep here. Vita activa, vita contemplativa. "Mary hath chosen the better part."

The Third Way reconciles both halves of this dumb-dumb rain.