Luke 4:5-7 King James Version (KJV)
5 And the Devil, taking Him up into an high mountain, shewed unto Him all the kingdoms of the world in a moment of time.
6 And the Devil said unto Him, All this power will I give Thee, and the glory of them: for that is delivered unto me; and to whomsoever I will I give it.
7 If Thou therefore wilt worship me, all shall be Thine.
All true. But consider as well that some of these people are simply hollow in thought as well as spirit. They don’t have to make a conscious or even subconscious deal with the devil. they get the same result being what they are naturally.
Granted, that has the same ultimate source regardless of their ‘belief’ but they have no need for a physical or spiritual devil when they serve as their own just fine. They do believe themselves their own Gods so it logically follows.