I cannot tell if you are joking, and that scares me worse than if you are completely serious.

I'm mostly serious, though I really don't know why 1×2 exists and why you'd build a part that supports it but not 2×2 (or, alternatively, that supports it instead of 2×1, which is, but for a name change, an older standard with the same nominal bandwidth), and the 2×2 will also support 2×1.

But maybe there is an electrical engineering reason why it might be practical to do 1×2 but not 2×1 in some device.

Probably it’s for cables, in that a 1x2 cable can (I assume) be longer for cheaper than a 2x1 cable.

1x2 requires lower frequency electrical signals I suspect? That might be preferable in some scenarios. Still insane.

Just wait, Usb 3.2 1x1x1x1 is just around the corner for high power draw devices!

Yes lower frequency. There is a big jump in implementing a 10G PHY vs a 5G PHY