Your DayZ theory is part of it. These post-apocalyptic games were very popular at the time. Arma is naturally responsible for yet another dogshit genre taking shape. Tarkov started development in 2012, which iirc is the same year pepsiman shitcanned the original STALKER 2, and members of that team went on to try and make Survarium, which was going to have a mode exactly like what would become the extraction shooter genre and even has shit like the eye of the storm mechanics from battle royale games:
The Freeplay map is much, much bigger than a usual PVP location. There are several large structures, which differ according to the risk and difficulty of gameplay. New players in a weak outfit will not be able to explore the entire map. The most dangerous areas will be available only to players with the best gear and access to some areas will require playing through the story quest chain.
There will be no time limit for gameplay in an area but there will be a limit on the number of players that can be in the location. We want to maintain an atmosphere of exploration and this is only possible when meeting with another player will be a rare event, not an ordinary situation. If one of the players dies or leaves the location, his or her place will be taken by a beginner. To leave the location the player must travel to one of the special locations which are located on the edge of the map where he will be asked if he wishes leave the map.
The game world continues without the participation of the players. Mutants periodically attack the survivors and the survivors fight mutants or each other. Each event is a source of side quests for players. Depending on which faction has the most players, the balance of power can be shifted and make story missions easier or harder. Events and mission locations are closely connected with the narrative plot. So the first location of free play will be fully dedicated to the events of the first season. Its content will vary, depending on how Survarium’s plot develops. (We will go into more detail about the development of the story in the last part of our developer diary).
Approximately every 2 hours of real-time the Storm will occur. About 15 minutes before the start of the Storm players receive a warning and the game world will stop allowing new players to join. In the allotted time, the remaining players must find shelter or leave the area, otherwise they will perish. After the storm has passed there will be a number of very valuable items scattered around the area. Survivors of the storm get a 10 minute head start to search for these prizes after which some of the prizes are destroyed and the location accepts newly connecting players.
Freeplay mode, among other modes, gives the player the opportunity to develop his or her character, gaining experience, reputation and money for completing tasks and performing other actions.
In addition around the map you can find items that will give you money, experience, and reputation but only if the player is able to leave the map carrying them. If killed all items carried by a player are dropped and can be picked up by another player.
battlestate started working on Tarkov in 2012 as well, and it’s a Russian developer, which explains why the game looks the way it does and takes place where it does. The stalker in there is literally “they take place in a really similar place” and the typical “we’re copying what’s popular” stuff. It has less influence on Tarkov’s actual gameplay than you would imagine, it has more in common with Arma. At this point Tarkov is more influential to STALKER considering how much the second one wishes it was Tarkov down to the item animations and shit. STALKER mods have also increasingly become like Tarkov in UI and gameplay to their detriment (see: GAMMA.)
STALKER could have been huge, probably, but they gave up on it. The Tarkov devs were the first people to actually release a playable game that was anywhere similar. They focused on all the least interesting parts of STALKER, which are the ones with the most mainstream appeal, turned it into something different, and now STALKER is derivative and way less popular than Tarkov