Indeed, imbuing such an already expensive armour would then also involve sending adventurers to obtain crazy components and cost the wizard involved at least one point of constitution which was not at all easy to get back in AD&D. There wasn't even an increase of ability scores through level progression, so the point was likely gone for good.
And then in came video games. "Ah crap, the twelfth dagger +1. Let's go back to the village and sell all the scrolls." Of course this impacted player expectations.
