Forced Hollywood Ending?
I remember watching this movie in the theater when I was about 17 and it freaked me out. I didn't need Nancy to tell me to "say no" to drugs after that! I've seen it recently on a premium movie channel in its entirety and still impressed by the pre-cgi cloud-chamber/composite photography that didn't look as fakey as I thought it would.
Anyway, it's the ending that I'm curious about. It just doesn't look like it was intended to end that way. It looks like the ending should have been more like Jessup and possibly his wife disintegrating into that great vortex of a higher (lower) level of being. I sensed that Chayefsky was pressured by Hollywood sensibilities of the time to concoct a happy ending perpetuating the old "love conquers all" axiom and that's why the end of the movie seems so abrupt.
Whether this was due to unfavorable audience repsonses in pre-screenings or pressure from the cinematic illuminati, it just looks a bit contrite at the end when compared to the deliberate pacing of the rest of the movie.