Its specs seem on par with the PS5 Pro, and this doesn't even have a price or a shipping date yet.

The PS5 is already about five years old, has had a slim release and a PS5 Pro. The PS6 announcement is probably a year away, with a 2027 or 2028 release.

Valve is launching a last-gen console, probably at a price that won't be competitive, right before the PS6 comes out.

I think Digital Foundry has expects the performance to be bit below the base PS5 in most cases. It has a new generation of CPU/GPU than the PS5, but less cores/ CUs. VRAM is also only 8GB, PCs generally need more than that to match PS5 settings.

Is console generation really a statement about performance?

Where does that leave e.g. Nintendo Wii, which is generally considered to be the same generation as the Xbox 360 or PS3, despite having not nearly the performance.