@Coin
Unless, of course, tons of people isn't the point and it's more like a large tabletop game where the small amount of people playing are having fun.
I was going to make a snarky comment, but it turns out I missed copying the last bit of what I'd written, which is that these ideas might work fine for a tabletop game, because the small handful of people would fit around a table and could be reasonably sure everybody else involved actually has an interest in exactly the same shit.
I'd dispute the 'large' part, though. Most of these ideas barely glean enough participation to be a normal sized tabletop group. Either way, they're shit for a MU*.
I'm sorry, theorycrafting is kind of fun for me. I didn't know everything had to have a solid, identifiable, realistic goal. Sometimes I just like to chat about what I would do if I did something, and never really do it. Gasp, right?
Sure, me too. Are you suggesting that if a handful of people started rambling about how they'd love to make a MLP-Transformers Crossover game, like Beast Wars only with magical ponies, and all using the WoD system you wouldn't think it was some silly shit that would never see the light of day? Because I'm about 99% certain that you would point and laugh.
Sometimes, an idea is just a terrible one, and I don't really feel any shame in ridiculing terrible ideas regardless of why they're terrible, when people start talking about them like they're not. Having known you to do much the same in the past, I don't think you really disagree with that, we just disagree on what constitutes a terrible idea this time. 
(And for the record: yes, I've seen small games with niche themes that have lasted upwards of a year. And a year, really, is a decent run for a small game; or any one instance of a hobby in which people are having a good time, especially now that we're not in our teens or laid-back twenties anymore.)
Again, we disagree on a pretty basic point. I'd consider a game that only lasted a year, assuming it was actually set up like an actual MU* and not just some mostly empty rooms for people to use like a tabletop game, to be an incredible waste of time. Especially given the more limited time people have to invest on a regular basis these days.
@Arkandel
And occasional even successful games have tried non-US settings - HM comes to mind as it was set in Vienna, Germany.
Leaving aside the Austrialulz, note that I said non-US, non-Eurocentric. There've been decent sized games set in Vienna or Paris, etc. Not so much Tehran, Riyadh, Khartoum, Damascus or Abuja. Cities I'd bet good money that most of the people reading this post couldn't identify by country on a best 3 out of 5 without googling, despite all being capital cities to have been featured on even the US news over the last few years. That's not to claim any superiority, I had to google a couple of them too. 