It filled a niche for gamers who had grown up playing HM on Gameboy, but hadn't been able to really scratch that itch. If anything, his choice of genre to work in was genius. It was a passionate and pre-made fanbase that was craving a new game to jump onto, and he happened to make an excellent game as well.
It also helps that HM is a highly generic game/genre. There's very little about what makes the original games popular that is trademarked. I played thousands of hours of a couple of them, and I probably can't name any of the characters any more. You can easily make an "off-brand" remake, and most people won't miss anything specific. You wouldn't be able to just go make a knock-off Pokemon and have it work, even though the demand for it on PC is high.
Word-of-mouth is marketing too. Perhaps you are thinking that marketing === advertising? Because marketing doesn't have to be advertising. Building a community, attending conferences, getting influencers to play your game - these are all marketing activities. If people are talking about the game, it's surely fueled by a quality experience but marketing has to bootstrap that conversation.
I'm not a marketing expert tho, but I can't think of any way to force word-of-mouth onto people.
>To make a successful anything, it's 90% marketing, 5% quality, and 5% luck. If the right person finds your product and endorses it, quality doesn't matter. You'll get guaranteed sales. It's then that it takes quality to sustain those sales.
I strongly disagree.
Stardew valley did well because it is a fun game with good graphics. That's it, it's fun and addictive, graphics are good and it gets the gestalt right. Stardew Valley is just a truly truly fun game in which you say "just one more day" a bit too often. It's just that much fun. The game is FUN and addictive. Did I mention I had a lot of fun playing it? It has nothing to do with marketing it had everything to do with how I played the game and whether I had fun or not. The first time I picked it up I poured in more than 40 hours in a single week! And that's a lot!
I just read this article about the creator who spent 4 years making Stardew Valley and it is a really interesting read:
https://www.gq.com/story/stardew-valley-eric-barone-profile