You may find this quote from Philip's Ex wife helpful
Dick's former wife Tessa remarked that "Ubik is a metaphor for God. Ubik is all-powerful and all-knowing, and Ubik is everywhere. The spray can is only a form that Ubik takes to make it easy for people to understand it and use it. It is not the substance inside the can that helps them, but rather their faith in the promise that it will help them." She also interpreted the ending by writing, "Many readers have puzzled over the ending of Ubik, when Glen Runciter finds a Joe Chip coin in his pocket. What does it mean? Is Runciter dead? Are Joe Chip and the others alive? Actually, this is meant to tell you that we can't be sure of anything in the world that we call 'reality.' It is possible that they are all dead and in cold pac or that the half-life world can affect the full-life world. It is also possible that they are all alive and dreaming." It is altogether possible to take Glen Runciter's convictions that he himself is alive and that the others are in half-life at face value, given Joe Chip's ruminations on the organic values of his own world's pseudo-reality at the end of the penultimate chapter. The reinforcement of this limbo state's 'reality' by repeated use of Ubik, as well as its prolongment via widespread half-life, could allow it to cross over into true reality by being set up as its parallel: just as Glen Runciter was able to impose his presence on half-life by repeated contact with Joe. Part of the confusion of interpretation is down to the mystery concerning the means of survival and escape of Glen Runciter following the explosion on the moon
I'm a fan of Philip K Dick as well but sometimes he's a little beyond me. My take is that the team were the ones in Half-Life but they didn't know it so reality was warped for them.
