Well, the tanks were kinda obsolete, compared how things evolved in Europe. But I don't think Japan really had that much use for much better tanks, as things fell.
Their Navy was fine.
But I think everything they did was undermined by the totalitarian structure of their militaristic society. They couldn't adapt. They were stuck in rigid and disastrous ways. Their doctrine was that they would win because they were supposedly superior, with a superior warrior spirit. What do you then do, when things go really wrong and you're losing? Banzai and Kamikaze. And why did they send out Yamato and Musashi on their last cruises? Utterly senseless.
That was IMO really the weakest side of Japan. They didn't have the sense to cut their losses or give up.
That they would lose was never in question.
I concur.
They were isolated from the world and had been winning many battles since WW1, so they were quite proud and it was fueled by their Samurai spirit.
Note: The tanks failed miserably while fighting soviet army.
Although the best aspects of Japan's forces was their Fighters and Infantry. Even as the losing side, they made a hell for American soldiers.
Japanese tanks having been obsolete is large attributed to their outdated combat doctrine. Like the French, and at least at the start of the war, the British army, they used tanks as support for the infantry. So by design, their tanks were never intended to fight against other tanks. They didn't need powerful armor penetrating cannons or lots of thick armor according to their combat role. And the fact that the Japanese didn't really fight a high intensity conflict since the Russo-Japanese War. All that time between, Japan steamrolled comparatively weak nations in their militaristic expansion (Korea, the island nations in the Pacific, a civil-war China, etc.), something which didn't exactly compound any necessity to evolve their combat doctrines.
When faced with armies using combined arms warfare, superiour numbers and up-to-date materiel/equipment, they got their collective teeth kicked in.
But yes, the biggest culprit was the ironically undisciplined leadership. Anyone who went to as much trouble as doing some simple economical projections (eww, math) would've seen how futile it is to try and pick a fight with the major powers of pre-WW2. As soon as the US and friends threatened to embargo the japanese oil imports, they should've known the gig is over. But the highly politicized military had such a raging warboner, they couldn't see the bleedingly obvious. Anyone who wasn't completely deluded knew this and any who actually opposed it and spoke out against this madness was instantly thrown out.
Japan defeated itself, the actual war and enemies therein where nothing but proxies of their own lunacy.
I suppose that's what happens when you base your national identity on a romanticized ideal about Bushido that was spiritually cultivated during a time of two centuries uninterrupted peace and not the actual Samurai ideal as it were during the warring period. Uesugi Kenshin and the other famous samurai strategists probably drilled themselves halfway through the planet as they rolled around in their graves, ethereally ashamed of their legacy being alienated like that ...