Take aways:

• Sample set is of 5 games
• Lenovo drivers are much slower than Asus
• There are 2 games where windows is neck to neck or better, 3 where SteamOS is far ahead

Some doubts:

• Did the author run the benchmarks few times to rule out shader compilation. 99%ile would be helpful.
• I wonder if it makes sense to test DirectX10, 11 and 12 games separately to better understand where Proton has an edge.
• I wonder what all settings can be tweaked in Windows to find potential fixes (core isolation, cpu boost, power profiles).

Point is Microsoft and OEMs need to do better, however not every game or subscription services work on Linux, so in the interim time users should know what they can do to close the gap better.

Did the author run the benchmarks few times to rule out shader compilation

Really grasping at straws there, eh? I'm no big fan of Ars but I hope we can assume they're not quite that incompetent.