Expressions (phrases, clauses, etc.), Noun
having very little difference between one another; being much of a muchness; being more or less the same; height comparison among acorns
Idiomatic expression
こういう流れになると結局、どんぐりの背比べになる。Once things start going this way, in the end they'll all be much of a muchness. pointless competition (between two equally unimpressive parties); pissing contest
Idiomatic expression
Also written ドングリの背比べ【どんぐりのせいくらべ】、団栗の背比べ【どんぐりのせいくらべ】