Why didn't Japan just make piloted bombs during ww2 or did they?
That they did, meet the Ohka, lovingly known by the americans as the Baka (idiot):
Effectively a manned anti-ship missile, and powered by a solid-fuel rocket, designed around the concept of speed, which would make it impossible to shoot down once airborne.
The problem was getting this thing to the target, as rocket-powered aircraft are notoriously short-legged (see the German Komet, an interceptor rather than a suicide aircraft), so they had to be carried to their targets by japanese twin-engine bombers, which in turn, were extremely easy target for American radar-guided naval interceptors, ensuring only three ships were ever sunk by this contraption.
Unlike the Germans, which put their fate in wonder weapons during the closing stages of WWII, inadvertently helping the shape modern warfare as we now know it, the Japanese put all their fate in bullshit suicide weapons, kamikazes, like this one, all with extremely poor results, and their only legacy post-war military-speaking being the proof of just how far the madness of men can really go.