The obvious thing that I can coming see is high bandwidth flash, which as far as I know is under active development by multiple companies.
From what I've read one architecture is basically RAID0 at the flash chip/chiplet or PCB level, combining many fast flash chips into one wide channel and then turning that into a wide fast streaming storage system. Fast as in competitive with DRAM, at least for streaming a lot of data, which is what most AI inference wants.
Flash, even very fast flash, is much cheaper than DRAM per GB.
I'd like a specialized local inference node consisting of 2TB high bandwidth flash, 16-32GB of DRAM (for attention and other state), and a big TPU. That could run frontier size models in something the size of a large mini PC like an Intel Nuc. The lower cost of flash would probably move most of the cost to the processor(s).
I wonder how feasible it would be to DIY a board layout for basically RAID0 flash that's pretty good? A bunch of flash chips in parallel. Use something like a cheap fast ARM or RISC-V chip as the flash controller and have it do striping and present itself as an abstract drive over a thunderbolt or PCIe interface.