However! Publishers don't do that. Publishers' value proposition is funding the development and doing the marketing for you, so that you can concentrate on making the game. If the game tanks, they eat up the losses (i.e. it's an investment, not a loan). The retail is a separate issue and, while it's handled by the publishers, is still likely to be handled via Steam or other platforms.
You also have to check if your customer is any other of the countries / states that collect VAT (India, Indonesia, many US states and oh so many random countries) and make a proper declaration in each country. It's almost impossible to do it right if you don't go with a partner to handle it all.
There is an alternative for online services, etc called VAT MOSS[0], mainly meant for smaller sellers which allow you to keep paying VAT in your own country without registering in all of them but you still need to apply different VAT rates depending on your customer's country. Also you need to keep records of these transactions.
Steam (and other services... well actually even Steam uses an external service for this) handle that stuff for you and you only deal with Steam.
[0] https://europa.eu/youreurope/business/taxation/vat/vat-digit...
Marketing seems to be the biggest draw for using a publisher these days. That and getting easy access to partner management with sony and microsoft. My understanding is that some publishers are even quite good at social media now, helping indies get exposure on twitch and youtube.
They’ll charge a hefty fee compared to doing it yourself, but still far below the Steam cut.
Although publishing on steam obviously has other advantages.
What if you simply do not do this? Are they going to arrest you? (Presuming you are VAT registered outside of the EU or whatever)
This is actually something that the Factorio developers (mentioned in the comment you're replying to) have had a lot of issues with. See "The Grey Market" (https://www.factorio.com/blog/post/fff-171) or this article: https://www.pcgamer.com/factorio-devs-take-g2a-up-on-its-cha...
That's why Kickstarter and Steam Early Access are such a big deal, they allowed new financing models and independent game-dev studios to emanzipate themselves from publishers.
Marketing
Localization
Covering development costs
Physical distribution
It is definitely possible to do marketing and localization alone as a company, but it will divert studio's focus from game development, which could do more harm than good since game development is insanely hard. Physical distribution is almost impossible to do properly for a small company. Of course there are game investors that invest into specific games and it could be better fit than publishers, but you can do both.
need to spent hours trying to install all that stuff
That is pretty much not a case.
I do think that the steam's fee of 30% feels strange, but all the infrastructure they provide is pretty sweet. How do you update the zip file you downloaded? Do you trust every developer to keep their download servers running forever so you can always download it later?
Well, this sounds like spyware (unless it is opt-in).
This is comparable to what every developer on every console has paid for over three decades in publishing, and still leagues better than what they were making from boxed retail sales.
I've heard that one of the appealing features of Steam for developers is how easy it is to upload new versions and generally distribute your game.
I also can reinstall hundreds of games from Steam without remembering who developed it, who paid for the development, or who published it to Steam. I just tell the Steam client to install it based on the name of the game. That's a great usability and convenience feature.
Yeah, double clicking on a game and having it automatically downloaded and executed... hours of work and hundreds of viruses! You have obviously never used steam and origin.
1. Download Steam client
2. Click to install Steam client
3. Steam client starts to download even more crap itself
4. Steam client actually starts installing
5. Sign In/Register
Then when you want to install or even play a game...
1. Launch Steam
2. [UPDATING STEAM, PLEASE WAIT]... Jesus Christ...
3. Sign In/Register
4. Click to install game
5. Launch game
6. [CHECKING FOR UPDATES, PLEASE WAIT]...
7. Finally play game
And if your internet connection goes offline? Enjoy, you're fucked.
Yeah, fuck Steam and all similar bloatware.
That is why EA owns so many game studios one big flop and suddenly you owe EA a couple of million.
tl;dr Up-front advance was important for cash flow and risk management. At the end of the day they ended up with less profit but think it was the right decision anyways.
http://weatherfactory.biz/state-of-the-factory-year-1/
Note also that there is a difference between a publisher (Humble) and a distributor (Steam), which is covered in that post.
In some cases a publisher makes sense, in some it does not.