Bethesda softworks publishes all games under the zenimax umbrella (BGS, Id, arkane studios) correct? But why doesn't it just say zenimax as the publisher? Why the need for the separation?
In 1999 Bethesda Softworks became a part of Zenimax.I would guess they continue to publish the game under the Bethesda Softworks name as it's most likely the stronger brand name, as they been publishing games since the early 90s.
Even though their new companies use the Zenimax name (Zenimax Online, Zenimax Europe, Zenimax Japan, Zenimax Sweden, Zenimax Germany, Zenimax France and so on). In just a couple of years they opened world wide publishing offices around the world, after just being a US publisher for ~15 years, and getting publishing help from Ubisoft, 2K Games and so on, they are now publishing games on their own.
Also, were the past elder scrolls developed by bethesda softworks? I found this on the wiki in regards to bethesda game studios..."Previously synonymous with parent publisher Bethesda Softworks, the studio's name and logo was established with the release of The Elder Scrolls IV: Oblivion in 2006."
The past TES games were indeed developed by Bethesda Softworks. But after publishing games by other development studios for a while, they wanted to make people more aware of the differences between Bethesda Softworks the publisher and Bethesda Softworks the developer. It was a pure name change, and didn't really change the internal structure of the company in any way, as they already worked separately.