Germans tried that at Leningrad, ultimately didn't work out for them, even though over a million Russians starved to death.
They also didn’t actually succeed in encircling Leningrad. They came very close to it (and cut the Moscow railroad, which was the source for most of the city’s supplies), but they did not encircle the city.
The US had encircled Japan by 1945. They already had an effective blockade up.
The Russians had General Winter on their side.
It’s hard to maintain an effective blockade/siege when the besieging force is being destroyed by starvation, disease, and freezing to death.
I agree with you, the idea that a blockade would have brought a timely conclusion to the war with Japan is fantasy at best, past posting at the worst.