When young, men are more anxious to be seen than understood, and in pursuit of visibility are happy to take credit for the vague and extraterritorial suggestions of rhyme.
As they age, men wish to set down their experienced vision in a precise and unmistakeable form, and as a result they feel rhyme as a constraint, and its chance illuminations as extraneous intrusions into their unique and personal insight. Blank verse, they believe, is a better instrument for the communication of their views.
Unfortunately, they are right; cool and pellucid, blank verse sets forth only what any educated and experienced man could say, and should only say in prose if at all.
Without comment, readers turn back to the work of those fervid younger men whose self-advertising use of metre results in a shimmering mirage of profound significance, a light that never was on sea or land or in any mind.