A querist asked, “So you do not see the cessation of demon possession as an indication that the devil was bound?”
I am not sure they were simultaneous. You remember that demon possession was being reduced during the ministry of Christ and the apostles (Mt 8:31, 12:27-29, Mk 7:26, Lk 11:19). At some point after that it ceased; probably about the same time as the prophets of God stopped prophecying. However, the Bible does not say that the demon possession ceased when the Devil was thrown into prison. We just have to guess. He is not the only bad guy. He is just the chief. The non-canonical work of Jubilees has the Devil complaining to God after the Flood that he could not do his job of tempting sinners if God threw all of his demons in the Abyss. God relented, and left him 10% of the total so he could be more effective in tempting men:
7,8 And the Lord our God bade us to bind all. And the chief of the spirits, Mastema, came and said: ‘Lord, Creator, let some of them remain before me, and let them harken to my voice, and do all that I shall say unto them; for if some of them are not left to me, I shall not be able to execute the power of my will on the sons of men; for these are for corruption and leading astray before my judgment, for great is the wickedness of the sons of men.’
9 And He said: Let the tenth part of them remain before him, and let nine parts descend into the
10 place of condemnation.’
I am confident that demon possession was minimal during the 1000 years from AD 345-1345. Other than that, the exact time that demon possession ceased is just a guess.