FTA: Thus, a CPU family intended to address higher-end systems will typically add 2 more bits of physical address* every 3 years.* For me, that loosely follows

FTA: Thus, a CPU family intended to address higher-end systems will typically add 2 more bits of physical address* every 3 years.* For me, that loosely follows from the “CPU speed doubles every 18 months” variant on Moore’s law. Having extra address space doesn’t help you if your CPU is too slow to fill it (1), so if your CPU gets twice as fast in 18 months, the amount of memory you can effectively address doubles. That would only change if we had non-volatile RAM. (1) yes, you could have a hash table with effectively zero chance of collisions if you were to use petabytes to store a few hundred items, and that would be useful even with a 1MHz CPU, but if you can spend that money on memory, you’re better of spending it on better CPU. So, that only would help if CPU evolution stopped and memory got drastically cheaper, both in $ and in power usage.