Uncompressed 2000 x 1000 x 24 bits x 24fps x 90 x 60 seconds is 777gb. However, there are lossless compressions that can take this down a bit, and there are "invisibly lossy" compressions that can take it a great deal further.

In particular, VBR invisibly lossy compressions are possible that are near-lossless in periods of complexity and movement, and very high compression in simpler scenes. So no, 100gb is really not too far off for this sort of film.

And more to the point, if it's costing you $12,000/year to store uncompressed, you start thinking about more lossy compressions pretty fast!