What other API are they supposed to support that has wide support and supports all features while not being tied to a specific ecosystem? Because as I said if they made a standalone steaminput driver that would require explicit support from developers (outside steam nobody else really interprets controller input the same way, typically they just allow the devs to do whatever). Its more complex than games just automatically accept any controller with any input method, they either need a stable API to call upon (which outside of steam is basically just xinput) or have a translation layer. Lets be honest nobody is going out of their way to support a standalone steaminput except maybe gog.