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.
Steam has been offering third-party titles since 2005 but still had no shopping cart as of 2008.
So 3 years? How long did that take epic? About the same time almost 2 decades later?