Why doubling Type 93 torpedo range would not guarantee hits

Would doubling the range of Japan's Type 93 torpedo make its surface fleet more relevant?

Not by itself. Long-range shots need reliable target information or guidance; otherwise the extra range mainly produces inaccurate speculative salvos.

The answer distinguishes the Type 93's cited 40-kilometre maximum range from an effective visual engagement range of about 22 kilometres. Doubling maximum range to around 80 kilometres would place the target beyond direct sight and allow ample time for it to change course. Aircraft spotting and a salvo of hundreds of torpedoes could create a moving minefield, but the result would remain uncertain. Homing is considered more useful because it could make the existing 40-kilometre range effective. Japan is said to have been working on some relevant ideas, although additional developments would be required. Wire guidance is offered only as another possibility. Early-war American ships continuing on straight courses might make distant salvos more viable until they adopted evasive zigzagging.