The existence of the leaked Fallout Legacy Collection, containing Fallout, Fallout 2, Fallout Tactics, Fallout 3, Fallout: New Vegas and Fallout 4, in addition to all associated DLC, has been confirmed by Bethesda UK on Twitter. Unfortunately they've also confirmed that it will only be available in the UK and Germany.
Fallout Legacy will release in UK and Germany only.October 4, 2019
Which sucks for bargain hunters in other countries. Fingers crossed this will make it worthwhile for Bethesda to finally update Fallout 3 and make it more compatible with modern versions of Windows, as stability has been a problem for that game for years now.
The Fallout Legacy Collection comes out on October 25. Which is coincidentally the release date of Obsidian's new RPG, The Outer Worlds.