Will the RS see a surge in sales and if so will there be enough supply?

[Ray]

Yes.
No.
My take is that the driveshaft issue is not as significant for the RS, as there is less travel in the swingarm.

Not sure I follow. The valve is there for drainage so I can't see how a difference in swingarm arc travel would affect entrapped moisture / water.   Besides, Darrell's RT has the valve from the factory. Surely that has similar swingarm travel as the RS ...

Agree - you have the right to feel left out in not being offered a duckbill valve at the low point on your swingarm - just in case you find some high water to run through.

(Personally, I don't believe my final drive will fail due to absence of an extra hole and (an easily lost) duckbill valve.)

I note that the service procedure includes some testing of the integrity of the drive train - this might simply be for data collection among the bikes of GS riders, who seem to be (at least on their fora) at high risk for final drive failure. 

I don't know. Maybe BMW hasn't seen much in the way of failure of RS joints or final drive. We're a pretty responsible group, and after Darrell's high-mileage failure, many of us have paid attention to what used to be considered routine maintenance. (I think I mentioned, one of the folks I know still has an old R shaft cased in grease in the PVC pipe he used to carry it as a spare on trips to Mexico.) In this context, I don't mind if my riding style and care for my bike are felt to somehow differ from those of the unwashed mass of GS bikes (if not riders). 

You are right - why include the RT and not the RS. The most recent models sport front/rear travel of 4.7/5.4 inch for the RT and 5.5/5.5 inch for the RS (always one of my arguments for the RS as a good bike for varied terrain). (GS comes in at 7.5/7.9 inch and GSA at 8.3/8.7 inch.)

That said, here's Ben Purvis' take on this isssue as found on the Bennetts site (UK) as to why RTs were included.... Which circles back to your original question. Aren't RSs used for "official use" like the RT? Don't they deserve similar consideration?

B Purvis - The problem appears to be that, in some conditions, water can accumulate inside the swingarm containing the drive shaft, whether due to ingress during off-road use or fording deep water or thanks to riding in particularly wet or humid climates. Although largely the same design of swingarm is used on many BMW boxer models, the GS is the target of the enhancement work because it’s more likely to be used in those conditions and its higher suspension means the universal joints in the shaft drive assembly are at a greater angle, adding to the strain on them. Hence the update only applies to the GS and to rare ‘official use’ versions of the R1200RT and R1250RT – the sort sold to police or perhaps blood bike services.
 
The work that dealers will carry out varies depending on the age and mileage of the bikes. All get a vent hole drilled into the lowest point of the shaft drive assembly’s outer case, and bunged with a rubber one-way valve that allows water to be drained from inside without letting water in. Dealers will also do checks for excessive wear or signs that bikes have accumulated water inside the shaft assembly and may replace some parts.  https://www.bennetts.co.uk/bikesocial/ne...vice-check