Wikipedia

[Pyrrho]

It looks like the 1250 is now mentioned, though barely.

Unless there's something new somewhere else I haven't seen, the only mention of it is in the R1200RS article with the line "For the 2019 Model Year, the R1200RS was succeeded by the R1250RS."

Look at the entry for the S1000RR in comparison.

I've also noticed that even BMW barely mentions the R1250RS in their own parts catalog.

Or on their BMW Motorrad YouTube channel. Separate and sometimes multiple videos on every other bike, except the RRS. Videos discussing new technologies that the RRS has like cornering ABS, the TFT, etc include shots of every bike except the RRS. On-the-scene reporting from bike shows where Motorrad reps are interviewed highlight the SXR and FXR as their performance sport tourers, GS as their adv tourers, and RT as full tourers. Occasionally they'll even reference a K1600, but only when asked directly about them. Nobody even bothers asking about RSes.

I get the impression that they wanted to kill off the boxer models and replace them with the K line a while ago but there was so much love from previous owners -- more specifically GS and to a lesser extent RT buyers -- it would have been financially injurious for them to do so. They still wanted a sport tourer though and the F & SXRs are those bikes for them now, with the RRS being a red-headed stepchild to somehow appease "those weird boxer people".

Why it's almost deliberately not marketed is more puzzling. Again just an impression, but it's as if the people into the RS in Berlin are a very small group and they're not liked very much. Personally, I'd want to give them all a big hug, thank yous, and offer to buy them a couple rounds of beer anytime I'd see them.

If I'm looking for factory accessories at an online dealer, I typically have to refer back to the 1200.

Larger BMW-focused accessory manufacturers have 1250RS-specific stuff but they're certainly the exception.