Yes, Rashputin, 66 was such an unfortunate number to settle upon considering the Book of the Apocalypse. You would think it would have been 65 or 67. But maybe God permitted the Bible to be whittled to 66 books to give a sign to the perceptive of where every man as an authority unto himself would lead in the End.
The Bible was whittled down to 66 books because Luther was desperate to get rid of direct statements in Scripture that contradicted his claims. Due to that fact, barring some indication in Scripture or in early Church writings by the Apostles or those directly taught by them that indicates heretics will come along and reduce what they accept to that number, I'd say it has a lot more to do with what Luther could get away with than anything else.
Folks who are focused on Self and Self Alone have become so used to cliches and superficial single verse doctrines that they don't even realize their defense of accepting only the Anti-Christ Pharisee Approved Luther Subset of Scripture is by definition blaspheming the Holy Spirit.
The only difference between such folks and the leftist useful idiots in this country who adopt whatever they're fed by the media is which media figures they blindly follow.
Non-Catholics have embraced what they once taught against at a rate directly proportional to the rate at which Christian media has replaced denominations as the primary source of doctrine for most non-Catholics. Given that media driven embrace of the same standards the non-Christian society embraces, Protestantism is clearly the foundation for the strong delusion Scripture says will lead so many people astray as we approach the second coming of Christ.
Regards