Which rather supports my claim that it is not itself a perfect construction.
If all you intended by your claim that the construction is
not perfect in modern English is that it is
not aspectually perfective in modern English, and you did not mean to insinuate in any way that you found the construction
not very good or
less than fully acceptable in modern English, then I apologize for misunderstanding you and have nothing more to argue here, my argument having been predicated, I now suspect erroneously, on the assumption that you were seeking to
pooh-pooh a perfectly good grammatical construction in Modern English, one which can be and often is used as an alternative to aspectually perfective constructions in modern English.