I read Manna, but honestly I thought it was silly.
> Terrafoam is, by contrast, 'Worse and worse.'
No, it's not. Manna is better and better: it yields continually better results.
> With all that happening, it is very hard to get people together to work on big projects.
Wouldn't it be cool if there were something to get people to work together on big projects? Something like an economic force causing them to give a little to get a little?
Frankly, I think the Australia Project would stagnate after a generation or two, while Manna would continually improve. After a few generations, it'd be much like to Communist states vs. the West: yes, the Communists did often improve on their initial conditions by quite a bit — but the free economies improved even more. I recall a story about someone (in China, perhaps?) bragging about how the government dumped a pallet of free cabbage on each city block every time period. Free cabbage sounds wonderful to someone who was a subsistence farmer — but Asian-American fusion cuisine on every city block sounds even better.
And that's just within the construct of the story. A real-world example would have competing Manna-like systems.
Also, in the Manna world the problem is that in the U.S. most people don't have the ability to contribute, and so they languish in Terrafoam. It provides no reason for why they are suddenly more talented in the Australia Project. That just doesn't make sense.
Anyway, I hope that mankind's actual future is not to choose between two different totalitarian systems.