The V trajectory is indeed broad, but that's what makes it iconic. You can find it also in trilogies like the original Star Wars or Superman films. The second film tends to feature a low point for the protagonist: Luke Skywalker loses his hand and discovers the truth about Darth Vader, and Superman loses his powers. These storylines are meant to appeal to Christianized audiences, of course, so that's why we should expect to see this V pattern throughout Western popular culture.

You may be on to something in your deflationary explanation of the V mytheme. I'm reminded of how the thought of Heaven is often ironically regarded as more boring and onerous in its way than the thought of Hell.