I don't think there's an "obsession" about storage, but it shouldn't be surprising that it keeps coming up. We have pretty good info on the CPU, GPU and RAM, but we know basically nothing about storage. That makes storage pretty much the only piece of the performance equation that's completely open to speculation, and this is a speculation thread, after all.
The other factor is that storage is an area where Nintendo actually can get close enough to allow for exactly those "Big , open world, AAA games designed around streaming ungodly amounts of assets through Direct Storage or similar APIs" without breaking their power or cost budget. The SSD of the PS5 in particular is absurdly over-specced, and even the Series X could have gotten away with a lot less than its 2.4GB/s. Considering the lower quality assets we'd expect on the new Switch model compared to these consoles, something around 1GB/s should be enough to prevent it being a significant bottleneck, and I think pretty much anyone in this thread would be happy with UFS 2.1 storage providing 1GB/s read speeds.
Here's a phone that launched two years ago for €200 with UFS 2.1 storage providing 1GB/s read speeds.
Storage like that isn't particularly expensive, or even particularly fast, to be honest. The latest UFS 4.0 based phones are hitting
almost 3.5GB/s in sequential reads. We'll likely see mid-range phones switch to UFS 3.1 next year (which has actually already started, with
this phone recently releasing with UFS 3.1 and almost 1.9GB/s sequential reads for €360), leaving slow, old ~1GB/s UFS 2 for the entry level of the market by the time the new Switch model releases.
Slow Switch load speeds haven't really been due to Nintendo cheaping out on storage, either. I can't find sequential read speeds for the eMMC used in early Switch models, but since at least 2019
in the Switch Lite they've been using the Samsung KLMBG2JETD-B041, which should hit around 300MB/s sequential reads (
Samsung advertises 330MB/s for the 64GB variant, so the 32GB module Nintendo use probably comes in a bit lower). Nintendo multi-source components like the eMMC, but they're likely using similarly specced parts when they do so.
Switch games aren't bottlenecked by the storage itself when it comes to load times, they're typically bottlenecked by the CPU having to decompress the data. Hence why Nintendo added a boost mode which increases CPU clocks during loading, and why higher specced storage would have been pointless on the Switch. Drake isn't the TX1, though, and in particular
it has a File Decompression Engine (FDE), which Nvidia seemingly designed specifically for Nintendo (it's not on Orin), and which should allow them to eliminate any CPU bottleneck when it comes to storage speeds. The fact that they went to the trouble of adding custom hardware like this is a very strong indication that Nintendo aren't going to cheap out on storage.
For external storage, as has been discussed many times, there are options. But the actual cost to Nintendo of supporting something like UFS cards or CFExpress is pretty trivial, as they use standard interfaces and should be able to be wired up directly to the SoC the same way an SD card slot can. I'm not sure about SD Express (it combines the old SD interface with NVMe, so might need an IC to interface correctly), but there are definitely options for faster external storage that cost Nintendo nearly nothing to support. Obviously availability and cost of the cards themselves to consumers is a different factor, but that's not a matter of Nintendo cheaping out.