[SapporoChris]

https://en.wikipedia.org/wiki/Precision_bombing#World_War_II "These provided impressive accuracy—British post-raid analysis showed that the vast majority of the bombs dropped could be placed within 100 yards (91 m) of the midline of the beam, spread along it a few hundred yards around the target point, even in pitch-dark conditions at a range of several hundred miles. But the systems fatally depended on accurate radio reception, and the British invented the first electronic warfare techniques to successfully counter this weapon in the 'Battle of the Beams' "

I do hope wherever you are from that your cities are larger than a few hundred yards.

[seabass-labrax]

The article you link to is about radio navigation based on ground stations. The USA would have required at least an island near the Japanese mainland on which to establish such a ground station, or perhaps a ship if it could maintain an accurate position based on traditional methods.

Even then, I don't think it would be correct to say that the Americans had no other capabilities for targeted attacks. With air superiority you can do strafing at relatively low risk, which is very accurate. And the USA had also developed rockets by this point, which could drastically improve accuracy when compared to unpropelled bombs. They even used these operationally against Japan before the atomic bomb attacks.