I’m not convinced this is a fact.
In Paul’s day, the term archon (ἄρχων) meant a human ruler or governor, not a demon. At least according the LSJ –--
http://www.perseus.tufts.edu/hopper/tex ... Da)%2Frxwn
As Bernard pointed out, when Paul meant to indicate a demon, he used the term daimonion -----
And Paul used “Satan” (Σατανᾶς) in terms of a spiritual deceiver or adversary.
I think the analysis related by GakuseiDon (page 1) using Psalm 2 provides a reasonable alternate solution for 1 Corinthians 2:6-8, and is entirely consistent with Paul’s modus operandi of using the Jewish scriptures to construct his system.
Earl Doherty in his Jesus Neither God Nor Man addresses the “rulers” in 1 Corinthians 2:6-8 (pp. 104-109, and then some), but I don’t find his arguments for demon spirits convincing.
I’m certainly willing to be convinced. Opinions, interpretations, and appeals to authority are all fine and dandy. But what I haven’t seen (maybe I’ve just missed it) is the term ἄρχων/ἄρχοντες (ruler/rulers) clearly used to refer to non-human demonic powers in any text dated to before the Roman-Jewish War.