You talk as if all Steam games use Steam DRM. No, it's not GOG but it's not the same category as Sony and Microsoft at all. It's starting to sound disingenuous when I see Steam lumped together with them.
I think it's a fair comparison. Steam can change their behavior to become much more user hostile at any point, and hold our triple digit steam libraries hostage.
Its not like we can sell or even lend the games from Steam that we have, not without breaking the licence terms and hacking around the DRM. Its precisely the same as what Sony is intending to enforce.
Can you sell or lend gog games, though? You can transfer the files obviously but if a steam game comes with no drm (which is pretty common for indies) you can do the same thing. GOG nicely requires everyone on their platform to do this but ultimately the devs have to want to not put in drm too.