Planetary Annihilation's $90 Alpha

Steam News announces that Planetary Annihilation is now available as an early access title. This is causing quite a stir thanks to the $89.99 price it carries, which is steep for a finished game, much less a pre-beta. They include a note somewhat addressing this, explaining that this is the price they told their Kickstarter backers that early access would command:
Our pricing for this stage of early access was determined by our Kickstarter. The stages of our early access for ALL users, which was determined during our Kickstarter, is:

June through August: $90 for early alpha access, during the time where we're still locking down features and making tweaks to the flow of the game. This access is permanent access - you will be able to play through alpha, beta and on through retail. (Galactic Edition Equivalent with all addons)