Hey, I wouldn't call it a pipe dream cultivated by scam artists. Mars has appeal purely for the exploration - just like any other planet. Humans will surely set foot on Mercury too if we don't eliminate ourselves sooner. Mars will never be terraformed and terraforming Mars is a terrible idea. But a reasonable sized human settlement for scientific purposes with a decent number of orbital habitats is in the cards. Over time, I expect most people living within Mars SOI will be living in orbit and perhaps going down to the surface to work.

I agree with your points OP. I think over the long term, the primary place of human habitation is going to be in orbital habitats (particularly O'Neill cylinders). However, Callisto is as you say one of the strongest candidates for a place for human habitation in the solar system - if not the strongest.

Callisto as the primary hub of the Jovian system seems like the most likely outcome. I think over the medium to long term, the Jovian system becomes the largest economy in the solar system - exporting tons of raw resources to other settlements across both the inner and outer solar system. It will likely get overtaken by Neptune eventually, but Callisto as THE economic juggernaut of the solar system for a period at least is not at all far fetched.

Europa is a terrible place for human settlement anyway.