That's no less than a 4 year wait. No more than 7, though, so, there's that. Fallout 4 will be out first, and Bethesda takes ages to do these things.
Fallout 4 announcement around summer.
Fallout 4 release, Fall 2015.
Fallout 4 DLC January 2016 - Fall 2016. First DLC is Xbox One exclusive for 3-5 months, then all following DLC is available for all systems on their respective release dates.
Final patch for Fallout 4 late Fall or early winter 2016, supposedly fixing all the shit Bethesda fucked up. It fixes very little, and fucks more things up. The PC crowd will have gotten these glitches and bugs fixed months ago, because modders always fix it before Bethesda even considers fixing it. Console users remain fucked.
Bethesda announces some other game mid-2016, and releases it fairly early in 2017 (no later than July). They remain silent for the rest of the year.
Bethesda announces The Elder Scrolls VI in Spring 2017. No one remembers the game that was supposed to come out.
The Elder Scrolls VI releases Fall 2018. The world becomes as white as Skyrim due to the collective orgasm and semen flood of the people playing TES VI. The flood occurs again on a much larger scale when a modder makes better HD textures for the PC version.