You are so unsure if the game will be featured in GOG that you claim it will never be because it doesn't sell yet at the very end of your post you state maybe they will.... HAHA!

So much for believing in yourself... End of Story.

Reading comprehension impaired you are...

Seriously, you've seen how he responds to others. Were you expecting something different? Why interact at all?

I have a feeling that UrW's submission was before ToME 4 or other Roguelikes came around.

Remember how the Avernum remakes were barred for the longest time because of the old business model stating old games only, and GOG told Spiderweb Games no at the time?

I'm sure they submitted it when they decided to try to monetize it on Steam . GoG looked at it, likely saw it was being "sold" for Pay What You Want (aka free) and passed on it thinking it would not sell enough.

Generally speaking, looking at the games GoG accepts or have changed their minds on, looks like they are shooting for the Steam equivalent of over 20,000 copies sold or more (without bundling). Since GoG sells about 15% of what Steam sells that translates to about 3,000 copies to be sold here.

Unreal World is estimated to have sold...
Owners: 5,255 ± 1,687
Or short of 800 copies GoG equivalent.

Remember GoG hasn't changed their mind on Mushihimesama
Owners: 21,588 ± 3,419
Where the devs have stated they want to be on GoG. I'm actually a bit surprised they didn't change their mind with those owner numbers.

Thea: The Awakening is an example of a game GoG changed their mind on
Owners: 40,336 ± 4,674

The player interest doesn't appear to be enough for GoG to reverse course for Unreal World. Those are just the facts.
And about 70% of any game's non-bundled sales comes in the first week of release on Steam.

And remember, it's not just genre. GoG likely makes a decision how well each individual game will sell here. They rejected it because they didn't think it would sell enough and for a game to change their mind, it's going to have to show better sales on Steam than Unreal World has.

And meanwhile, gOg have also released the best selling titles such as Obscuritas,....

The funny thing about UnReal World its that it does not have the greatest sales numbers, but it is is still raising at the same pace, which I find interesting, I had expected it to slow down more by now.

Everyone makes mistakes right?

There's more to GOG than just selling games. Sometimes, they just like to carry a game because they like it.
(I don't know if that is the case of Obscuritas, but day 1 releases are always a gamble).

True, it's hard to judge if something will sell well.

Those kind of percentages are rumours, there are no accurate estimates, and I guess it would largely depend on genre and game.
In fact, in the case of Primordia it was a lot more than that (which surprised the developers, as they expected a lot less).

But, anyway, the more a game sales on Steam, the less potential customers you have to buy it on GOG. And GOG has one thing Steam lacks. Better storepage promotion. So my guess is cult and niche games would fare better on GOG than on Steam (not in absolute numbers, I mean relative to your estimated percentage). Would it be enough? That's a different question.

As an example, when Oxenfree was added to GOG (March 14th) it was bellow 20,000 in Steam (and I don't know how long it takes to reach an agreement, so it was probably sooner when they decided to carry it). And yet it is now at 23,000. Why? My guess of the later bump would be Jesse Cox's let's play. For indie games, each small bit of promotion can be huge.

About 15% is the number released by two separate developers. And your source that GoG sold a higher percentage than that for Primordia vs Steam is where?

But let's talk Oxenfree...according to Steamspy, it had more Owners than Unreal World the 4th day after release compared to Unreal World after a month. After a month, Oxenfree was in the 16,000-18,000 owner range. More than triple the Unreal World sales and well on it's way to cracking the 20,000 barrier.

This is a game which is matching the observed pattern. GoG makes their best guess whether a game will be good enough for a Day 1 release, then if not and a game proves successful enough (which looks to be in the 20,000 owners sold without a bundle range) it will add it later like Oxenfree.

Amok always wants to cherry-pick Day 1 releases which were not so successful, but frankly, a few games' failures is not a good argument for bringing other "niche" games to GoG.

Edit: Another thing to consider is what was the competition for release that week. It's possible some of these games were released here like No Pineapple Left Behind or Obscuritas, because that was the best GoG could do for a day 1 release that week. I've previously posted about the stellar cast of games GoG released the same week instead of Unreal World...

Because aswell as offensive to others I found him amusing.

~350 already