I would resist the urge to give too much credit to luck and marketing when it comes to indie game success. Notable outliers like Bastion, Sword + Sworcery, and FTL were all stunning executions. The FTL team did almost no marketing, but released a product that spoke directly to the target market of desktop gamers. Passionate people played it, liked it, and told others.

It's hard to achieve that level of success because it's hard to execute on that level of excellence with a concept that resonates with an audience.

There are other paths to financial success, surely, where monied studios can pump out derivative crap with in-app purchases and virtual goods. I guess the talent there comes from being able to tune experiences designed for shallow addiction, like food scientists creating the cheese dust for Doritos. But I don't think that's the only path.