I don't think we'll get to the next teir with out a new type of hardware and also a new rethinking of computing.

I think the limits are thermodynamic and we're not going to get there with current architecture. We need a kind of computer that's much more highly networked and that runs much cooler. My suspicion is that a highly networked system will inherently draw less power for the same compute.

Examples: human brains, plant plasmodesma, microbial networks.