The Bridgestone tire that was OEM on European Insights was discontinued many months ago, so I expect the same to happen with the RE92 eventually. I don't know how one could find out whether this has already happened. Maybe the fact that dealers are listing them as backordered rather than discontinued is a good sign assuming that dealers actually know what Bridgestone is doing.
European Insight owners have been substituting other fuel-efficient tires. Because gasoline is much more expensive in Europe and there are many more small cars that use 165/65R14 tires compared with in North American, European Insight owners might have a wider choice of fuel-efficient tires. But even so, I don't believe that any tire has been found that is more fuel-efficient than the OEM tires that Bridgestone made for the Insight more than 11 years later

So the search continues…