First of all, that's not what ablative means. Tiles potentially falling of does not make the heat shield ablative. Because tiles falling off is not a the heat t

First of all, that's not what ablative means. Tiles potentially falling of does not make the heat shield ablative. Because tiles falling off is not a the heat transfer mechanism, rather a mechanical failure. The Dragon Capsule for example has an Ablative Heat-Shield. But that doesn't necessarily mean it can't do multiple missions in a row. It just depends on how the shield is designed. The Dragon could potentially do many earth missions without replacing the heat shield. Second, you are wrong in that there is anything fundamental about Starship or Shuttle heat shield not being able to fly multiple missions. If the tiles are still attached and not damaged, then all that has to happen is for the tiles to cool down. After that they are ready for another flight, meaning the tiles are not ablative. Now experience on Shuttle has shown that if you are not careful tiles could fall of or be damaged. Damage can be reduced in various was and Starship without an external tank is already much better by design. Additionally Shuttle had to glue tiles to a fragile aluminum frame making the installation very hard and the tiles very fragile. Starship on the other hand uses welded studs on a steel frame. So even if a tile is lots, the steel should still hold up pretty well. In on case Shuttle was saved because there just so happened to be steel under a damaged tile. So you are right, heat shield is one of the biggest issue that could cause problems with rapid reputability. You are wrong, the tiles are not ablative cooled. But Starship tiles are totally different then Shuttles, they have made many improvements in the heat shield and its construction and in the heat shield tiles themselves. Starship can likely survive even with a number of missing tiles if required. In some position tile lose can certainty be fatal.