His mentioning DRM was ancillary to the main point, that you don't buy digital goods in the classical sense, but instead lease the right to use/play them. This applies to every form of software that has paid-for licensing, even those that don't have DRM attached to try and protect it.
You are still buying a "lease" to use the software from GoG. I'm not completely familiar with their license agreement, but I suspect it allows you to install the software on all computers you use/own. If you were to give it to a friend, that would be violating the terms of the agreement (even though GoG could not stop you).
The agreement may allow you to resell your license, provided you stop using your existing copies. (Again, GoG would have no way of knowing.)
So don't pretend that only games have this issue.
It's not even an issue to me. I'm not sure what your point is.
I was just trying to clarify that game purchases are still essentially software licenses, even from the least restrictive providers (GoG).