And the mega bucks to be thrown at the E-3D for upgrades if it has to soldier on to 2035. I would imagine, however, a further shrinkage in the the number of airframes and crews/Sqns with the the rest being stripped for spares.
Assuming the NATO commitment/offset can be met of course - it may/may not be cheaper to run it on rather than fold it and have to fund the NATO E-3A force. I would expect the costs are close, but the flexibility to cover the FI task and OOA would make it preferable.
And, indeed, the 737 Wedgetail may come into the picture as a replacement, but not I imagine for at least a couple of decades until the P-8 bill has wound down.