Wait so since this is a custom SSD does this mean we'll be buying proprietary ones for storage upgrades ;__;?
Yeah, this sounds very unlikely to me. Unless they really want some insane console prices.
The PS5 has to be cheap.
The SSD will be small to keep costs down for the base-model console, which means it has to be expandable with external drives or cheap upgrades. Games will become increasingly large.
It's not going to have highly customised unique technology. Sony learnt their lesson from the Cell processor. They'll use off-the-shelf parts with relatively little customisation, especially for the one part that has traditionally been upgradeable/expandable.
It'll almost certainly be an M2 drive with a PCIE interface. Maybe even SATA3, which they'd need if they support for external expansion drives (SATA3 is just as fast for PC gaming as PCIE, because sequential read GB/s is not the bottleneck for game loading)
Even an off-the-shelf consumer SSD will be a major high-cost part for a console.