My bro Paul appeared to believe that also
1 Corin 8:5 For even if-ever there are ones saying to be gods, whether in heaven or on land, even as there are
gods many, and lords many, 6 but to us, there is one God the Father, out of Whom the all-things, and we into Him; and one Lord Jesus Christ thru Whom the all-things, and we thru Him.
http://ourworld.cs.com/preteristabcs/id84.htm
The Thessalonian church was comprised primarily of Gentile converts from the pagan cults of Dionysus, Zeus, Asclepius, Aphrodite, Demeter, and perhaps most important, the cult of Cabirus. They were converts from a social and religious milieu in which gods and demons were understood to have control over virtually all aspects of life.
Given the unique nature of this Pauline doctrine in a letter which is supposed to correct eschatological misconceptions, it must be asked if it is appropriate to assume that Paul is here innovating a completely new teaching. Proper pedagogy elucidates the unclear by the clear, not by the unprecedented. Why would Paul have concocted a general assumption of all believers, a doctrine which has no basis in any other Jewish or Christian teaching, in hopes of alleviating misunderstanding among the Thessalonians regarding the fate of their departed?