Well, we don't really know how hyperdrive works. Maybe there's a reason only starships are capable of hyperdrive. Maybe an asteroid would just break up immedi

Well, we don't really know how hyperdrive works. Maybe there's a reason only starships are capable of hyperdrive. Maybe an asteroid would just break up immediately. Maybe there's a discontinuity between hyperspace and realspace so that they're not always 1:1. In other words, maybe it's extremely easy to miss or otherwise be unable to hit. The scene in TLJ is presented as a go-for-broke situation, after all. Maybe it's something that only works over extremely short ranges because deflector screens will bounce the attacking or defending ships out of the way.