Run flat tires tend to weigh more (inertia losses) and have worse rolling resistance (friction losses). I can't see how they could not hurt range/efficiency.
Every thread I've seen on them so far has said they were worse than the LRR alternative. Maybe if you are used to heavy tires that have crappy rolling resistance you wouldn't notice, but the inherent disadvantage would still be there.
You're just another person whose poor opinion of them was solidified by older generation products and continued bias.
As I've said repeatedly they have pros and cons. The biggest advantage they have is that you don't have to change a spare or wait on roadside assistance in most situations.
Goop and an inflators? Sure, they work pretty well, and don't save you any money. Shop will charge you to degoop the tire & rim and it's not cheap. In many cases TPMS sensor is ruined.... so often on par with the cost of replacing a punctured run flat. Newer Michelin run flats can be repaired unless it's sidewall damage.
Fuel economy? This one gets thrown around a lot as if it is an inarguable fact, but the reality is that in current generation products the differences are minor.
Don't believe me, trust your "many threads" you've read? Well, here's what GM says;
GM also said run-flats are 20 to 40 percent heavier than a conventional tire because of a thicker sidewall. They also have higher rolling resistance, so they reduce fuel economy by about 1 to 2 percent, GM says.
1-2% which is in line with what I said and is similar to fuel economy losses from other causes like larger rims.
I have driven plenty of high performance cars both with and without run flat tires, including newer 911 and Vettes, but I'm sure the Prius crowd is way more knowledgeable about tire tech in current gen high performance cars.
Traditional tires are preferable to me, and as I've said repeatedly I don't recommend running run flat tires on a vehicle that doesn't have a suspension tuned for them.
Run flats have their place, such as getting a flat and being able to limp up to 50-75 miles on the tire without having to stop... which in some cases is inconvenient and in others is dangerous.
