From what I understand the Beta was originally not even suppose to available for those who had not participated in the Kickstarter.
So when the decision was made that it would it would probably have felt like a slap in the face to all those Kickstarter payers who did pay extra to be allowed to play the early versions of Wasteland 2.

I find it kind of understandable but perhaps in response any future expansion or other game will be a closed Beta again that is only available for the people who participated in the Kickstarter.