Manyoshu, an 8th century Japanese collection of poetry

The Chinese Tang poetry used five and seven characters. That may be where it came from. Those poems rhymed, but that may have something to do with the two languages. https://en.wikipedia.org/wiki/Tang_poetry

I like short poetry and stories. Jokes are short as well. In English where the language allows both rhyme and accentual meter I can see how an even number of lines and syllables in a line would dominate with the odd number of lines or syllables appearing for variety. One has the five lined limerick which could be written as a four lined poem with a longer third line. I can see how five and seven make sense for Chinese and Japanese especially since writing them has a nice rectangular shape.

I like my jokes in the 5, 7, 5 format.