And? They were irrelevant to the course of the war - they were cut off from their supply, and were in insufficient numbers to threaten anyone.
The next planned offensive was what is now Malaysia to retake Singapore and re-establish control over the strait of Moluccas. This would have joined up the Southern front to the Western and secured the passage to India.
The problem is that the only way for Japan to actually maintain control over these vast territories is through shipping. They had no overland path from Japan to Korea, to China to Vietnam. Instead, they supplied their troops by sea. Now that they no longer had the forces to supply their troops in Burma and in SE Asia, the forces had to make do on their own. Most hunkered in for attacks that did not come (as they were irrelevant).
Japan had bigger priorities than to maintain troops in Burma when they were under interdict. This the IJN understood back in 1944 with the battle of the Philippine sea. They knew that once their internal defensive corridor was breached that they couldn’t maintain the shipping from Japan south - exactly the problem they faced at the start of the war.
This is why Spruance chose to attack there and not elsewhere. Japan could not afford to lose and would direct the majority of their forces. This was expected.
Japan later on, in the Battle of Leyte attempted to protect their shipping corridor one last time by throwing the remainder of the IJN’s large surface fleet. Checkmate at this point was inevitable but the hope here at Leyte was to delay defeat.
The point isn't that they were relevant - it's that every direct interaction with actual Japanese who were not prevaricating diplomats playing for time indicated that they had no inclination to surrender. Even the Germans "surrendered" only when Berlin was overrun. The Japanese were known for fighting to the last man and, in the post-war era, for holding out for decades past the war's end. The idea that the Japanese would put up less of a fight than the Germans short of some massive shock, might or might not be ludicrous, but it certainly ran against the experience of every encounter Allied forces had with them. Eisenhower's comment about the Japanese inclination to surrender sounded like his way of passing the buck - since as President Truman had taken ownership, why let any of the dirt get splashed on him?