But then I would have to install Steam, create an account, have it running in the background. And in case of macOS I would have to install Rosetta as well.
It would be better if they released drivers instead.
The Steam client is free and well-supported on all gaming OSes. It also provides Steam Input, which ensures customization parity with Steam Deck. In Valve's eyes, cross-platform support is already here.
A custom driver could always be made by the community. It feels a little absurd to expect Valve to write and support four different gamepad drivers, when they only need one.
I don’t think steam needs Rosetta anymore.