Yes of course, but if they see that the newer games just don't sell because everyone already has them from Steam or Humble Bundles, I bet they wouldn't go even for that trouble.

For a digital distributor "not selling well" is not really an issue, at least is a much lesser issue than for physical one, they don't have stocks, warehouses, etc... so the cost of having a game on GoG, if you don't have to work for months to make it run that is, is rather minimal.

So even if those games don't sell well or simply don't sell as well as other games, it's a lot easier for them to become profitable and they don't really lose anything by offering them.