I would say that Mormonism would make it even less likely. In my experience (I was raised Mormon), they tend to be even more ideological than southern protestants. That being said, the TRAX does connect with Temple Square, which I'm sure provides some utility to Mormons even if they only use it to avoid parking problems for General Conference (2x per year).

Honestly, I think the defining attribute about SLC was that they did what they set out to do, they did it within budget, and they exceeded ridership expectations. It basically silenced all the ideological opposition and let the projects be judged on their merits.