It's the consumer bandwagon.

The luck involved is that enough people found out about his game, played it, then recommended it to others who did the same.

They released a solid game with fun gameplay, great music, and an eye-catching art style. They priced the game competitively, even considering international pricing. All of this seems like choices that were made with intention, not the roll of a dice.

Okay, going with your logic, what about the games that have all of this and still are commercial failures? There is literally no shortage of them, even if you personally haven't heard of them.