On the FAQ, they point out that they don't know exactly what the licensing and pricing model will be, but that they intend to make it open source but also have a business model that supports development:

Look, we're going to level with you. We really don't know. We have two overriding priorities:

First, we want to put PanGui into the hands of as many people as possible and make it as accessible as possible. Second, we would prefer not to starve to death.

The extreme version of the first priority is making PanGui fully free and open source for anyone and everyone. The extreme version of the second priority is creating some pricing scheme where people have to pay us exorbitant fees just to glance briefly at an impressionist painting of the source code.

Clearly, neither will work out, so our goal is to strike some balance between these two extremes, preferably getting as close to the first one as possible. If you have any opinions or ideas, we would love to hear them.

Please tell us what to do As of this moment, we think PanGui is very likely to be some sort of open source, and hopefully the vast majority of people using it will never have to pay a dime. If we can make that work, we will.

I guess, because the problem they are addressing is acute.