FFS! I want all of my games on Steam - I already have Steam, Ubi, Epic, Battlenet and Origin launchers and I rarely, if every, remember to play something that isn't on Steam.
I've been on Steam since 24th September 2003 and, as a customer, Steam is where it's at for me.
Put your game on the other platforms, too, just don't try and get me off Steam or ask me to support you in crushing Steam (looking at you, Epic Fail Store).