With games that can't be resold they're able to price the initial game lower, and keep the profit flowing in. It removes places like gamestop from the equation(so they hate it, of course). Consider that I can buy many year old initially $60 games from steam for like $10. Because the game is still being sold, there's still incentive to fix/patch/expand the game.
But publishers don't lower the initial game price from the goodness of their hearts. New releases on Steam still cost (typically) 50 Euros, that has not changed compared to pre-Steam times. In short, publishers try to charge as much as the market will tolerate and pocket the extra profit.
Now there are a few people like me, who strongly dislike "services" like Steam and will buy less than before (and that preferably from DRM-free sources like GOG). But it seems that we are too few to make a difference.
Unless you count the success of crowd-funded games (Kickstarter) as an aspect of that dislike. Which it may be, but I don't have the data to prove it