Samsung may end SATA SSD production soon

Samsung makes fast expensive storage but even cheap storage can max out SATA, hence there's no point Samsung trying to compete in the dwindling SATA space.

Does this mean that we'll start to see SATA replaced with faster interfaces in the future? Something like U.2/U.3 that's currently available to the enterprise?

NVMe via m.2 remains more than fine for covering the consumer SSD use cases.

Problem is that you only get pitiful amount of m2 slots in mainstream motherboards.

Three is not pitiful. Three is plenty for mainstream use cases, which is what mainstream motherboards are designed for.

We used to have motherboards with six or twelve SATA ports. And SATA HDDs have way more capacity than the paltry (yet insanely expensive) options available with NVMe.

We used to want to connect SSDs, hard drives and optical drives, all to SATA ports. Now, mainstream PCs only need one type of internal drive. Hard drives and optical drives are solidly out of the mainstream and have been for quite a while, so it's natural that motherboards don't need as many ports.

> Now, mainstream PCs only need one type of internal drive

More so it would only need one drive. ODD is dead for at least 10 years and most people never need another internal drive at all.