"trading some consistency for availability can lead to dramatic improvements in scalability"!???
Wow! That's just great! Why not go all the way: an 100% available system with no consistency whatsoever? Oh, wait, we already have that in Google App Engine!
Neither of these is reasonable. You can't yield consistency - it is more important than availability. What's the user in having information available at 100% when you don't know whether it will be consistent?
I think the key is "eventually" consistent. As long as you can determine when the data are consistent, I think it bears some consideration.
I don't generally care about today's sales in real time. But tomorrow, I want all the data to be consistent, and I want to know it is consistent when I get my reports.
I don't think that BASE is at odds with that concept.
Amazon runs most of its stuff on eventually consistent systems. They do pretty well, as you can see, so your thesis of "A is clearly more importnat than B" is disproven.
Though this one has got some advertising on the print friendly version now.