Why only on Play Station?

They asked and I said 'no'.

I think The Frozen Wilds is included in the Zero Dawn complete edition for PC

Probably because Sony expects way more money from GOG versions of their games than they will actually receive from GOG versions of their games, since GOG has a vastly smaller customer base than St*** does.

The Frozen Wilds DLC is included in Horizon Zero Dawn Complete Edition for PC, and Forbidden West is the sequel. Horizon Zero Dawn was exclusive to Playstation for a longer time, too, and only recently ported to PC. So it's not that surprising. There is still hope that it will one day come to PC as well, probably dependent on how well the PC edition of HZD sold.

I don't think there's hope. HZD was released on Steam waay earlier than on GoG and it was never announced here. So nobody expected it to be released here and everyone already had it on Steam.
I can't imagine that it was a success on GoG.

Did you forget to log into your alt-account?

Edit:
Also, you know full well that The Frozen Wilds is included in the PC version. You were already playing it 2.5 years ago: https://www.gog.com/forum/horizon_zero_dawn_complete_edition/frozen_wilds

You sound like the older brother in Jurassic World. "Gigantic mobile creatures which are also an unparalleled feat of Science and very few people get to see them the way I do, yawn". Maybe Call of Duty with a Dragonforce soundtrack is more your speed.

A cool premise alone does not a good game make. Nor a good movie, as Jurassic World aptly proved :D

Not sure why you got so upset that you felt the need to play the super lame "maybe random thing that's probably supposed to be insulting* is more your speed" card, I just expressed an opinion and meant it to be humorous (though the opinion is honest), it wasn't an attack on fans of the game.

*I assume from the tone, I honestly have no idea what Dragonforce is and what its combination with Call of Duty is supposed to denote.

If you want more games from a company, that company needs to see that it's worth there time unfortunately.

Maybe if a surge in purchases of the first Horizon happened here they would give GOG another shot.

Honestly need to get Sony more involved anyway though as they do hold the IP's for a lot of classic games like Lemmings.

Zero Dawn is currently on the 262nd position on the all-time bestsellers list (gog.com/games?order=desc:bestselling&page=6) which may amount to, I don't know... at least a figure in the 5, maybe 6 digits range, in regards to sold copies?

Also, the PC port of Forbidden West hasn't even been officially announced yet.

Zero Dawn PS 4 2017 - PC 2020.
Forbidden West PS 4/5 2022 - PC not before 2025.

Hope that that little M$ vs SONY tiffy has no effect on the PC release.

Fair enough and sorry for the rudeness. I'm of the mind that any open world with good controls and performance is automatically good for relaxation and stealth is my ideal speed because it demands attention and rewards caution. A pity perspectives aren't automatically communicated.

Dragonforce is a power metal band that infamously speeds up all their music, and their "Through the Fire and the Flames" is the most difficult song in Guitar Hero history. (This is my only factoid regarding Guitar Hero, as rhythm games provide even less freedom than point & clicks.)

Well, I was talking about a PC port in general. Whether it would come to GOG or not is another topic.