Let's not be stupid, and recommend an hour long video without a link (it's here) as an answer to why 30% is a good deal. He says it loud and clear, but also it's hidden somewhere in the hour long talk. Like I said, 30% must be worth it if so many developers are willing to take the cut for the services. But if a big part of what you're getting is the number of users that use your platform, then you're in a bit of a loop. The 30% is worth it because so many people will see your game, and users don't leave steam because it's where all their games are. The users have incentive to stay, because it's nice to keep all your games in one spot. I have over 1,500 games on steam, so for me to leave steam would mean leaving behind thousands of dollars worth of content I paid for already. So how can another service enter the arena and have any viability? 30% might be fair, but it might also be too high. What if it doesn't matter if it's too high because they get more sales on Steam? It's a complicated topic, but I'm just saying that 30% of each and every sale is a pretty big cut, even if it has become standard (a standard set by steam).