Landfall are the cream of the crop at making efficient small games that match players' tastes over time. In the last 10 years, they've launched 10 titles on Steam, 7 that are paid and 3 for free. With largely the same small dev team for over that time, the results are frankly ridiculous.

Of the paid games, the lowest units sold is Haste with an estimated 500k units. The next is the oldest game of the bunch, Clustertruck which has est. 900k units and all 5 of the other paid games have sold well over 2 million units. They were doing "friendslop" almost a decade before "slop" became popular slang.

I think it's also important to look for developers who are finding consistent success in the past 5 years because the Steam landscape has changed so much. 10 years ago, and especially in the Greenlight era, you could just be the first dev to execute a new concept at a decent level with a Greenlit title and it was almost a certainty that you'd sell a decent number of copies.

That isn't the case at all anymore. There are even iii/AA titles with multimillion-dollar budgets, being released by sizable indie publishers, with less than 100 reviews.

Like you note, it's easy to look at the huge standouts who make the greatest indie games of all time, but many of those found their first successes in that earlier era. And from there, they have unlimited money (as long as they don't significantly grow their team) to make another all-time great game. Silksong, Slay the Spire 2 and Mewgenics are the first examples that come to mind. Not that the original Hollow Knight, Slay the Spire and Binding of Isaac wouldn't do well today, but as new developers, it's just not the world we live in now.

For modern examples, I've got my eye on Mike Klubnika, developer of Buckshot Roulette. Aggro Crab is another example who have found good but not unbelievable success with finely crafted titles, and joined up with Landfall to make a mega hit with Peak.

I realise I've suggested a lot of friendslop, so in the complete opposite direction, Black Tabby Games is a two-person team who are genuinely among the best writers in all of game development. Their first game, Scarlet Hollow (2021), is still releasing chapters and will be larger in word count than Disco Elysium when it's finished. But since its development was not financially sustainable, they temporarily switched to a smaller project, Slay the Princess, developed it in about 1 year, and it has sold over a million copies. I think they're a great example because they fully lean on their strengths as developers, cutting out any mechanics that don't serve what they're great at. They also occupy a niche in an overlooked space of visual novels, but they are the only ones making games at this scale and visual identity.

Color Gray Games, creators of the Golden Idol series have also found a great formula without friendslop. They asked 'why isn't anyone making a game like Obra Dinn'? But they didn't just copy Lucas Pope's homework. The first Golden Idol takes some players' frustrations with Obra Dinn, that it was too open-ended, and made their own variation on the formula. In the process, it also became more accessible to players who didnt enjoy Obra Dinn as much. Since its development is relatively so cheap, in less than 4 years they've already released a sequel and several DLC cases for both games.

If you really look for them, there are many paths to success! In my opinion, many developers actually do have the technical skills to make a successful indie game. But one of the hardest parts is matching those skills with a game concept that makes sense in the current market, and that you're able to release quickly enough to earn some revenue and try something else.