From the opinion piece:
Last year, I pointed out how many big publishers came crawlin’ back to Steam after trying their own things: EA, Activision, Microsoft. This year, for the first time ever, two Blizzard games released on Steam: Overwatch and Diablo 4.
To me it would be more uncompetitive for a game to be priced 10x on steam and be basically free on other platforms.
It’s not about what the publisher sets as price, it’s about restricting his options.