Yep. Valve takes that cut and serves up your game (and its patches) on demand FOREVER. No need to fight for shelf space, or bicker with store management on product positioning or any other shit. When a gamer wants your game, they get it, and if they're looking for something that might be like your game, they'll find yours, too.
I also remember reading an article from way back when that said that brick and mortar revenue cuts were at _least_ twice what Steam was taking. Perhaps this memory is totally wrong... with today's Google I'll certainly never be able to find the source of the memory.
most indies don't (and usually shouldn't, unless mobile) target casual gamers, and they can't bet on "stumbling upon a random game" to sell.
That stuff isn't easy but fortunately Valve isn't the only one offering that, and pretty much every other storefront offers lower rates if that's important.
Sure, but when your game is selling in the double digits, that's not something you can bet on. Discoverability is a multiplier and if an indies' is very low, Valve doesn't help there. You gotta pay $100, so I need at least 14 people to "stumble" and buy my game just to pay that back. Then I need 140 people so I can get that $100 back.
If valve wants to earn those 3 dollars, they need to ensure my game can be discovered to begin with. "becsuse there's a lot of people on steam" doesn't cut it these days. That was valuable at one point but I'd say aroind 2014 or so it ceased to be so.
I can't say if it's truly worth the 30%, but I sure don't want to be handling all those services myself or through others.