My mind forgot that M.2 is probably more prevalent these days and that they’re not just shutting down for no reason.

Is it though? Pretty much every single current-gen mainboard still comes with a number of SATA ports.

Everyone is going to buy M.2 SSDs first, and only buy SATA if they don’t have enough M.2 slots. I really doubt SATA SSDs are selling well. With that said, I don’t see SATA going anywhere. It’s (comparatively low) bandwidth means you can throw a few ports on your board and not sacrifice much. For some quick math: a M.2 port back-hauled by PCIe 4.0 x4 has 7.8 GB/s of data lines going to it. While SATA 6.0 has only 0.75GB/s of data lines going to it.

Even then, NVMe riser cards are a thing to just stick an NVMe drive in a spare PCIe slot.

Does require you to have the PCIe lanes for it, BIOS support for booting to PCIe (which Intel 6th gen core CPUs were the first to support. 4th gen never did but some had m.2 slots and NVMe support for secondary drives and the 5th gen X99s had some receive BIOS updates to support but that’s its own can of worms) and both Intel and AMD have historically been pretty bad about being stingy about PCIe lane availability Plus to run more than a single NVMe on a single slot your motherboard either needs to support PCIe bifurcation which is almost exclusively an enterprise feature or they need to have the right lane configuration available to support that x16 slot handing out 4x4 lanes (or 2x8/2x4 for dual NVMe)

both Intel and AMD have historically been pretty bad about being stingy about PCIe lane availability Hold up, I thought some of the nicer AM3+ boards using the 990FX chipset had a fair bit of lanes available.

Y'know what, I honestly haven't looked at what the PCIe lane layout is like on newer chipsets. Maybe it's gotten better since I last really paid attention like 5+ years ago. I remember in early-mid AM4 there was a lot of grumbling about how there's only 20 PCIe 3 lanes followed by early PCIe 4 platforms that would give only 16-20 lanes with another 8 or so PCI 3 lanes. I also didn't really pay much attention to AMD before AM4 given how far behind Intel they were. But I could be entirely out of date now that I think about it