I agree that Mini Metro is the one of the listed games that I would be least certain about. I think however it is very polished (more than other "puzzle" games) and it strikes a nerve because the design is very familiar to people using metros or buses.
Papers Please is a very special case. It has a very unique idea and that's what makes it stand out. You are right that you need to play it. However if someone played it he will most certainly recommend it and that's the strength of this game.. the implicit "marketing" it conveys.
You obviously always need some marketing be it a only dev log or whatever to at least get the core group interested. For a game like PP that really should suffice to get the ball rolling.
And certainly don't underestimate the number of people who are borderline obsessive with transport networks, trains, and anything involving traffic (myself included). Almost any game that adds a good gameplay element to managing or routing trains or traffic is going to do OK. Cities Skylines has done well with this crowd, too, after SimCity decided to start focusing on "Sims" style games and ditch the traffic aspects.
I then showed it to my wife who is not a gamer at all. She liked the trailer too but thought the player would be one of the immigrants :)
It's tough to make a perfect trailer..
I have to disagree with this (well, the second part of your assertion anyway; I absolutely agree it's a cool and unique game!). Just reading the premise of Papers Please was enough to hook me. I just knew I would like it, and wasn't disappointed when I actually bought it.
Also, all of Lucas Pope's games are visually distinctive, and Papers Please is no exception. I absolutely cannot think of any other game with a similar visual style which wasn't also made by Pope.
Interesting. I think you're right about half of those. I can't see any way that SDV or Darkest Dungeon could have failed. SDV is a great all round game with tons of polish, and DD has 99th percentile art direction and atmosphere for an indie game.
Mini Metro and Papers Please could absolutely have been dead on arrival. Mini Metro is just an above average puzzle game (of which there are tons), and PP is a really cool and unique game, but there's tons of games with similar art styles and it's impossible to understand what's good about it from a trailer. It's really one of those "you have to play it" games (aka "sells 0 copies in 99 of 100 alternate universes" games...)