That reasoning fails flat given the same studios have no issues supporting iOS, PlayStation, Swift and XBox, which are completely alien to what is used on Android NDK, APIs that are GNU/Linux compatible for 3D rendering, audio and asset loading.
Valve basically failed to provide the business value for those studios.
> given the same studios have no issues supporting iOS, PlayStation, Swift and XBox
PlayStation and Xbox don't go and cause you constant churn, at least not in the same console generation, and maintenance churn on iOS is only bearable for app developers because there are so many people using it that you can afford to pay the extra effort.