I'm not disagreeing, but Steam went out of their way to support Linux because they needed to, when they first dipped their toes in selling hardware (Steam Machine, circa 2013 I think).
GOG had no incentive to do so when Linux gaming was such a small slice of their pie. And now that it's growing fast, they still have no incentive to do so, because third parties are already doing the work for them.
At the end of the day, we gamers are still the beneficiaries of the immense effort of CDPR, Valve, and the whole open source community.
OKAY, BUT WHY ARE WE SCREAMING AT EACH OTHER?