BMW generally put crap RFT tires on many of their cars. These were cheap (to BMW). Sold at deep discount to BMW to let them capture a market of dumb consumers that just ‘get the same’

So, ‘all run flats suck’ became the truth.

Even when more mfgs came out with really good technology.

Look at some of the higher end brands. I like Michelin, but there are others. The stiffer sideways that might be a downside on a 3 series is great on a bigger X5. Love them on our diesel. And I have a spare