To be fair, the bulk of Luther's disputes with the church were about doctrines which were either medieval, or had been around but not particularly promulgated until the late middle ages--e.g., indulgences had been around for centuries, but until the printing press they were not readily available to all the figurative pew-sitters.
If anything, Luther was bringing back much of what had been Augustinian doctrine, which had been affected by all the medieval attempts to compromise the pure gospel, with Plato in the early middle ages, or with Aristotle in the later middle ages. So it wasn't that Luther knew more than 16 centuries of church leaders, but rather that the church leaders of the 16th century had forgotten a lot of what the early centuries of church leaders had known, and Luther helped bring it back.
well said