Games that were made by Psygnosis are now property of Sony Interactive Entertainment. Sony apparently has no interest in selling the old games they own, as they are not on Steam, GOG or anywhere else.

The main reason I'm bringing this up is because they are sitting on Drakan: Order of the Flame and also Rollcage. Luckily, I have the disc version of Rollcage, but I'm sorely missing Drakan.
These 2 games deserve to be sold again. It would be a shame for them to remain forgotten just because Sony can't be bothered.

Is there any chance they might appear on GOG one day?


EDIT
Also forgot to mention Overboard!. Another great game buried by the Sony colossus.

AFAIK - no new info, no.

You answered your own question:
"are now property of Sony Interactive Entertainment"
So they are lost to the abyss.

Sony is publishing some games on Steam (as PlayStation Mobile, Inc.), but, unfortunately, nothing old.

Psygnosis was a very prolific developer back in the day, but like any prolific developer they produced just as many mediocre games as good.

And Lemmings! How could you forget about Lemmings?

Didn't they publish the Discworld adventures as well? And I was always curious about the Ecstatica games, although I'm not sure if they'd (still) be fun to play.

So, can we safely assume that they are abandonware and can we treat them as such?

Nope, the term abandonware means they have been abandoned. These haven't been abandoned, far from it, its just you can't have them.

Well of course they will sell some games on Playstation, but that doesn't change the fact that the PC versions are unavailable by "correct" or "standard" means. Not to mention that Drakan isn't even on the PS store. I've been following the state of the game for a while now and there hasn't been even a mention of Drakan in forever, which for me honestly is enough to consider it abandonware. We are talking about Sony here. They are not suddenly going to re-release 20 year old PC version of games. They have 0 reason to do that.

You can have them easily, just without buying them :/.

These are games that haven't been available for almost 20 years. Of course Sony will never say that it is abandonware but some of the games show all signs of being abandoned.

But they have every reason to issue a DMCA takedown if their games are uploaded somewhere, no matter the platform. Nobody can stop you from downloading the games you want, but don't say it's legal, when it's clearly not.

If this games are "abandoned", then try to sell them on your site.

Nobody said anything about selling the games instead of Sony. Just their unavailability.

Drakan is available for download on many sites. If they cared, they would ask them to remove it. ISOzone even has a dedicated place for such actions and they will react almost immediately.

http://www.theisozone.com/legal/

I'm not saying it is legal, far from it. I'm just saying that if you have no other option, what are you going to do? Sony can't receive my money and I can't play the game.
Anyway, let's wrap this up or we could be bickering about moral issues regarding this for a long time.

The TLDR is that the games will not be available any time soon, if ever, and everyone can make do with this information as they see fit.