Fair.

Other than the “not actually a monopoly” argument, I think it’s important that Steam has that marketshare because they add value. They have a stranglehold on the market similar to the way BarCodes do. You don’t have to register your product with the bar code authority, but it will sure make your product more accessible to more people.

And that’s before cloud saves, achievements, patching infrastructure, community forums, game recording/streaming, and other stuff built into the Steam client/API.

Whether that’s worth a blanket 30% is absolutely a conversation worth having. Maybe it should be a sliding / bracketed scale depending on revenue or units sold or something. But like you said, the big lawsuits are coming from competitors, not smaller developers.