"Hard Drive" doesn't necessarily mean that. We still occasionally see articles say Blu-Ray DVD (which is equally infuriating to my technical sensibilities). A 1TB NVMe isn't out of the ball park and, frankly, if that load time is what it is and the amount of RAM is still 8GB, .8 seconds to load everything it needs into RAM sounds just about right for a PCIe 4.0 spec NVMe. NVMe is also getting cheaper faster than 2.5" SATA SSDs did and if this isn't out until next year production hasn't been finalized yet. If we get up to 8GB/s transfers on PCIe 4.0 NVMe, that lines right up with filling the game's memory footprint that quickly. They could even double the RAM by the time production starts and we'd still be, real world, at less than 3 second load times.
That and, frankly, by the time production starts I'm wondering if they can get costs to produce down enough that it can still hit a $400 price point. It's not impossible even if it means taking a smallish loss to keep their hold on market leader.
