But, does a "designed for mass production and cost target" transmitter
fall into that category?
It's not a published spec

You mean you haven't read the spec.

--- Hmm. don't see any tolerance on the output impedance spec on my
IC-7000.. page 150 of the manual: Specifications.
All it says is:
Antenna Connector: SO-239x2/50 ohm.

Page 11, where it describes the back panel
Antenna Connector [ANT1][ANT2} Accepts a 50 ohm antenna with a PL-259
connector.

Page 15, provides a recomendation that the load impedance have a SWR
1.5:1, and a boxed warning that at SWR higher than approximately
2.0:1 it drops power.

The service manual isn't much better, although it does have a
calibration procedure for the built in SWR meter, where you attach a
50 ohm dummy load and set to SWR=1, and then 100 ohms and set SWR=2.
That just calibrates the meter, though, it doesn't imply that the
actual output impedance is 50 ohms.


*I have seen this objection too.
When I've offered just such specs, objectors have then recursed back
into how output Z is unknowable and immaterial as if the topic had
never been encountered before.

ARRL doesn't measure it when they review rigs

Now THERE's an authority! *Do they measure efficiency?

At least they do some measurements and they publish their results.

They do measure efficiency, in a round about way (e.g. they measure
output power into a dummy load and they measure DC input power).

jim