I think games like that, where it's a small team and they grow to great success from essentially just word of mouth, are very much lightning in a bottle. It's not just a case of good game design, it's the right kind of game for the time, and well as a fair amount of luck that the snowball starts rolling at the start. It is true that the conditions have more or less never been better for it to happen (arguably it was easier before the market was as saturated as it is now), it's just very rare for it to happen to any given game, even with good execution.