Even at a "ridiculously low" price of $500k, you're basically offering a mount Everest experience for people. Dangerous , uncomfortable, generally hard to do if you're not super free. A crazy adventure
Some people are interested, but you can't argue much for economy of scales when the total market of affordability is probably tiny.
Only 5000 people have ever climbed Mt Everest.
People want to go to Mars. People want to try and live there. Scientists want to go there and learn, and explore.
On the other hand, people know what to expect from the rock that is Mars. If Mars was an unknown and people would want to go there to discover what's there, then the analogy would be correct.
Of course, people will still go, but reaching a critical mass for an unnecessary settlement (at which point it might turn slightly more alluring for more immigrants) remains to be seen. But I guess what happens happens, we'll see.
Absolutely, but then just one of these things will dwarf the ISS all on it's own. The old equations of space exploration affordability are being rewritten.
As for people wanting to go, there's a permanent base at the south pole, the peak of Mount Fuji is often a churned up field of mud from all the visitors and Burning Man looks like a ton of fun. Ok so some of that is frivolous. I'm ambivalent about the idea of Martian cities in the next 30 years say, but who can really look further ahead than that?
There's nothing that seems un-achievable about BFR. It seems to me these things will be going to space, and the Moon, and Mars at a ludicrously low cost compared to previous space missions. The real question is what will we do with that capability? I'm guessing we are going to do something with it. Musk's graphics are explicitly aspirational, but we'll do something with these vehicles and its going to be a heck of a lot more than any other plans I've ever seen.