The text here makes a couple of claims that seem to be wrong: (bold mine)

progressive
A screen using “progressive” rendering displays each screen fully, and needs no special treatment.
Most modern screens, and all computer screens, use progressive rendering.

And:

Note: At the time of writing, all known implementations match scan: progressive rather than scan: interlace.

These suggest that (scan: progressive) should match in the general case.

However, the results for this WPT test show that all 4 major browsers agree that @media (scan), @media (scan: progressive) and @media (scan: interlace) do not match.

I assume the text is just outdated, and was true when this section of the spec was originally written. Perhaps a more useful note would be something like:

Note: Most modern displays are not scanning, and so will not match any value for scan.

As a side note, it seems odd to me for a test to make assertions about the device. Getting a worse WPT score because you're using an old CRT or some other unusual hardware setup doesn't seem desirable.