You know why GSC is being very silent on mod support? Because it will be a) non-existant or b) castrated to hell. The reason being they're supposedly making the new STALKER on Unreal Engine, which means that any sort of modding ability will have to be added by the devs and it will probably be heavily limited anyway.
The reason the original STALKER trilogy had so much fan content made was because of the janky ass X-Ray Engine made in-house by GSC devs. It's a very adequate name as basically all the major elements of the game itself are contained in pure text files. You want to make yourself invulnerable to almost everything, have infinite stamina and infinite carry weight? All you need is a file manager and Notepad.
Not only that, GSC at some point released the source code to the X-Ray Engine, meaning the community was able to fix it up and expand on it. There is a project called OpenXRay which aims to improve the old game engine, however it only supports Call of Pripyat, with support for Clear Sky in the works and Shadow of Chernobyl compatibility being non-existant.
However do note that all the major popular mods are based on Call of Pripyat. Plus, Call of Chernobyl uses it's own modified X-Ray Engine, and STALKER Anomaly has it's own fork of the X-Ray Engine called the Monolith Engine, which is the most technically impressive fork of the original codebase to date, it's even natively 64-bit, and the amount of shit people manage to pull off in Anomaly speaks for itself.
And this is why no matter how fucking perfect STALKER 2 will be, it will never ever overshadow the legacy of the trilogy, as GSC decided that going with Unreal will be the best option, completely killing off any chances of a successful modding community.
And as for Bethesda, the reason they still allow modding is because they are still using their in-house engine that is essentially a massive fork of the Gamebryo engine that dates back to the 90's, which is structured in such a way that modding is actually possible. If Todd Howard ever decides to move to Unreal, expect the modding for Bethesda games to be completely dead, or at least neutered to hell. Not because Bethesda wanted it that way, it's because they couldn't do it any other way when switching to Unreal.