The announcement that Fallout 4's mods would be making a home for themselves on console as well as PC was a surprise to many. However, in a statement to IGN, Bethesda's VP of Marketing, Pete Hines, said that the Fallout 4 mod tools won't be complete until at least some time next year.
Hines said that Bethesda's focus right now is on finishing the game proper, then they will get to work on the Fallout 4 mod tools:
Nobody cares about mods if the game sucks. This has always been our philosophy. We shift energy to construction tools, the creation kit, and all of that stuff once the game is done, and we start to figure out what all of that is going to look like.
Bethesda is currently in the process of creating the platform for the mods and mod tools, but it is still a good time off:
The idea is that [the tools] will work on all platforms, but the truth is the system doesn’t exist. It’s still being built and worked on and it’s going to take awhile. It’s going to take clearly into next year because we can’t even start it ...
While modding may be many months away, Fallout 4 is due for release in just over three months. The next three months will have to be filled with something else, but come November, Fallout 4 should be enough to tide you over until you can get some more ... Fallout 4, but with mods.
It's worth noting that Fallout 3 did not launch with mod tools either. Fallout 3 released in October of 2008, with mod tools arriving in December of 2008. That's not a long wait for sure, but this time around they have a bit more work to do to get mods ready for both PC and consoles. There is also the integration with bethesda.net to consider, which seems to be a big part of Bethesda's future plans as a hub for upcoming titles, like Fallout 4 and DOOM 4.
I know it will be disappointing to some, but in my opinion we are all far better off with having the base of a game be pretty good so mods will have something to build upon. The Fallout 3 mod scene is still thriving, so we all know Bethesda isn't going to neglect them for too long while many of them are waiting to jump on into Fallout 4 and see what they can do.