A lot of that is the lack of SRAM scaling. There’s still quite a bit of improvements in the back end (metal traces). That aside, if foundries adopted say a 1T-1C SRAM we’d see a pretty rapid density doubling
MRAM is 1T, non-volatile and supposedly has nanosecond-scale write times so it naively seems like it'd be an ideal SRAM replacement. But I guess shrinking MTJ is more difficult than other components or there are some other limitations.
> 1T-1C SRAM
Aka eDRAM? It was a thing back on 14nm node, but AFAIR not so much anymore. The 1C part is hard to get right in a way that is compatible with a logic process.
Is 1T1C SRAM a technological thing or does it mean "persuade designers to use DRAM in the many cases where the retention contract could be timeboxed with a bit of extra thought and cross-team haggling"?