Beta is something they work constantly on. They polish things change things in terms of interface, dialogues and so on. Beta is something you should constantly feedback about balance and through their changes. That will normally take many month if they do it for real. Wasteland 2 for example had a Beta, Divinity had a Alpha and Beta and there was a constantly change in these ones. If you give people the beta 2-3 month before release that means 1-2 month before everything should be finished than you will not get the needed feedback.
With all due respect to inXile, the "beta" they released wasn't a beta. It wasn't even remotely feature complete, and has gone through dramatic changes since.
I guess you thought you'd be a big part of the design process for PoE? Other than those backers at tiers including items, that was never how this project was pitched in my recollection.