No. The duplication is seldomly that clean. It has started to diverge in subtle ways where the question becomes whether that was the intention or not. In the worst possible cases it has resulted in 8000-line functions full of duplication. 're-architecting the whole system to remove a bad abstraction' sounds fear mongering. That never happens.

Ah contraire, mon ami, I am currently in the process of doing just that in many places in my current codebase.