Just my two pennies worth but when a run flat is driven with no air you would be hard to notice the difference and hence the tyre warning system raison d être. As I may have previously mentioned, I replaced rf's on my BMW for conventional tyres, the change in ride, noise, handling, grip and most importantly tram lining, was night and day. RF's just have certain characteristics that in my view ruin all aspects of the drive. No doubting their convenience in terms of getting A to B, but they are not as common a tyre as conventional, so that "convenience" may be tempered when you discover it could take many days to source a replacement.
When the time comes, mine will be changed out for conventional and a can or two of gloop.