Since the release of the first instalment in The Witcher trilogy CD PROJEKT has sold over 25 million copies of The Witcher games.

Oh, they also made some money. ;)

https://www.cdprojekt.com/en/media/news/cd-projekt-posts-strong-results-2016/

Good. Means they can pay whoever owns the rights to Star Trek A Final Unity whatever they ask and finally release it here.

Not really...
Looking at the statements, the GoG division made $1.2 million profit for the year, but actually lost about $200,000 in the 4th quarter which historically is their best quarter. The annual profits are less than half of 2015 and the worst year I could find....

2016: 4,811,000 PLN
2015: 10,442,000 PLN
2014: 7,105,000 PLN
2013: 9,513,000 PLN
2012: 8,247,000 PLN

1 USD ~ 4 PLN

The games development division seems to be doing great, but that doesn't mean they are going to throw money away and take a loss from GoG.

So, does it mean GOG sales (and market share) are decreasing if profit is also decreasing?

The market as a whole seems to be doing great if their games creation division is any indicator.

GOG's sales are increasing, see page 30 of this report:
2016: 134 million PLN
2015: 116 million PLN
If I remember correct from CDPR's autumn results, GOG also contributes to Cyberpunk 2077 and Gwent and so also has costs for these unreleased games. No idea if that is valid.

Page 31 shows that GOG's selling costs have gone up by ~50% (does this cover the Fair Price Package?)

Strangely in 2016 they made only half as much profit as they made in 2015 (that might've been what you meant with the selling costs?). From ~2.6 million dollar > ~1.2 million dollars.

Was honestly expecting GOG to be making more profit than that but it's profit nonetheless I guess.

Could 2015 figures be greatly influenced by Witcher 3 sales which may be the main reason for the huge increase in profit that year.

Decreased profits don't say anything. They could've expanded, hired new staff, rented a new office, etc.

Hookers
Blow
Hot Pockets

It takes a lot of things to keep their staff working at peak proficiency. :D

Okay, so sales increased, but less strong than costs have increased.

I wonder why costs have increased so much? 50% increase is like a small explosion. Is it infrastructure like bandwidth of the downloads? Did they hire a hundred new guys? Are they selling below price to gain market share?

Because...gogBear: The Movie costs a lot to produce.

In theaters, 9.09.2018.

Released two weeks before they answer the Bizdev questions ;p

Just a guess based on observations here on the forum, but I'm guessing a lot of that is support. GoG has dramatically expanded regional support - even the forum and website have several language / region versions. And they're constantly hiring region specific support staff as they expand.

So I'm guessing the operation as a whole is doing something similar. Not to mention entering the (again, I'm guessing) "the beginning of the end" stage of development on Cyberpunk AND creating the infrastructure for both Galaxy and Gwent.

Plus, as you make it "big time" you find that everyone wants a piece and you start to NEED those sharks that begin to circle ;) Finance directors, specialized lawyers, high class hookers and the best blow - no more of that cut garbage... ;)

Chris Pratt? Damn, and I was so looking forward to that movie untill now :(