Well even at the worst (from a Protestant viewpoint) it had to be able to give rise to Martin Luther and others. Can’t be utterly dead for that.
The bible says wheat and tares. It never said how much of each one.
I once made the mistake of explaining this to a staunch catholic apologist with a closed mind, and I pointed out to this individual that even the stained glass windows could be used to bring someone completely illiterate to Christ during the darkest periods.