For the record, most (not all) of those quotes are taken somewhat out of context. Even in 1950, it was trivial to come up with examples of sets with more than (for example) 2^32 elements.

When it comes to address space allocation (ie IPv6) I agree; I'm skeptical that 128 bits will prove to be sufficient. But as far as simple enumeration goes, 2^128 is unimaginably large and I don't see how changes in computing could possibly affect that assessment.

An example. Partition a 2^128 address space evenly between 2^64 individual computers (it's difficult to imagine humanity ever possessing anywhere near this many devices). Each computer does nothing more than visit each value in its segment of the address space sequentially. No additional computations, nothing, just visits it. At 1 value per nanosecond (ie 1 GHz) this otherwise pointless exercise requires approximately 585 years to complete.