One optimistic and still very-non-consensus belief I have about the far future of cryptography:

I think that there is a 33% chance that, for average real-world computation, there exist ways to implement all three of what I call the Egyptian God Protocols (SNARK, FHE, iO) with 1+ε factor overhead (meaning, for large enough instances, the added overhead of cryptographizing a computation becomes arbitrarily small compared to the base cost of doing the computation itself)

And a 60% chance that all three can be done with single-digit overhead (ie. <10x, measured in total cost of energy plus amortized compute)

I think there's a good chance we'll get one of these (probably SNARKs with single-digit overhead) by the end of this decade. After all, we're already there for specialized hash functions and for some LLM inference.