It's not the almighty Steam or nothing anymore.
It shouldn't be. But it is still by far the storefront with the largest base of consumers willing to spend money on games.
My philosophy is thus. I believe all games should be available in all stores. Much like how physical games are. Now, not all stores may want to or be able to carry all games, but all stores should have the ability to carry any game available. This unfortunately, isn't the reality currently.
Now, it certainly may be that Epic will want to keep Fortnite only in their store, but if they choose to do so, they do so knowing full well that they are leaving a LOT of money on the table that they could be making.
This is why unless there are contractual obligations preventing it, all successful F2P games eventually put their games on Steam.
To put it more succinctly since I tend to get wordy and things can get buried in a wall of text. F2P games, from what I've observed tend to do the following.
- First, launch the game independently as much as possible.
- In the case of browser based games, this means initial launch on places like Kongregate or other such sites (like Crusaders of the Lost Idols).
- In the case of independent non-browser games, this means launching initially on your own website through your own store (like Warframe).
- In the case of one of the big publishers, this means launching initially in your own store (like Fallout Shelter).
- Once you've plateaued look to partner with other services. Usually this means Steam, GoG, the MS Store, etc.
You almost always launch first independently as you maximize your revenue. But your potential audience is going to be greatly limited and you'll soon reach saturation with that. There's not much point in launching though an established storefront unless you aren't capable of supporting the infrastructure to launch independently.
Once you're basically losing more players than you are gaining (IE - revenue is now dropping), you put it onto another storefront and get an immediate boost to revenue and userbase. Sure, you now have to share revenue, but that's better than continuing down the downwards spiral of losing users, which makes your game less attractive (if a multiplayer game), which means you lose more players, which makes it less attractive, etc.
I could go on and on with listing Micro-Transaction based games that have gone through this. The ones that haven't? They're basically all dead. Of course, putting it on Steam, once you start losing player retention isn't a guarantee of reviving your player base and thus revenue, but it gives you the greatest chance to do so.
Regards,
SB