Most people have one drive. Everything else is cloud based now. It's horrible 😭

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 0.75 GB/s of data lines going to it.

Yeah, but I think SATA is quickly being relegated to large mechanical storage drives. For things that don't require performance, like storage and what have.. because SATA is not getting any faster, I doubt anyones gonna come out with a SATA IV standard at this point, when PCIE over M2 is easier, simpler, and faster, and.. outside of silicon shortage stupidities, getting cheaper and more affordable.

Comes with them, but only for legacy media. Outside of my NAS I haven’t bought a new sata drive in probably 10 years. And I haven’t touched my onboard sata ports in 5.

The fact that they’re still there impresses me at this point. But their numbers are slowly dwindling. Sata is usually the first thing that gets dropped when you need more pcie lanes. And even then most boards only have 4 at this point. They’re switching back to those god awful vertical ports which tells you all you need to know about their priority.

Most people at least put their OS on M2. I guess if you haven't upgraded since M2 became common on motherboards you might not.

Edit: I internet says M2 was common around 2016 2017 motherboards.

SATA is not intended for fast storage devices but bulk storage, at this point.

They definitely have. The smaller form factor is better for laptops, and if you can share parts between laptop and desktop it's cheaper.