When mAbs come into play, the numerator will be considerably higher than $8B, IMO
Currently total US biologics market in 2015 is expected to be about $100B - but I'd expect >50% to still be under patent protection. So total market of about $40B (and this would include multiple mAbs in the $40B). And EU experience says that without substitutibility that the biosimilars get, perhaps, 15% (aka $6B). Hardly seems worth the fuss -g-.
That said, I agree that the plethora of generics may all be assuming the other guys can't actually do it - but this too seems odd since the European experience says there are plenty of generic manufacturers capable of biosimilar.
Given all of this I speculate that the lack of interest by the generic manufacturers in sub biosimilars is:
1) 40% uncertainty about the approval path for sub biosimilars through the FDA (hopefully a large chunk of this gets addressed in the next month or two with FDA release of regulations - and the remainder in the subsequent 18 months as Momenta drives the process)
2) 40% that it is technically in-feasible currently (Copaxone approval may solve 1/2 of this - but the remainder may take years to prove to a sceptical audience)
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