Why were the allies so aggressive at the end of WW2? I'm referring to the Battles of Berlin (≈ 350 000 Russian casualties), Iwo Jima (≈ 25 000 US casualties), Okinawa (≈ 60 000 US casualties) etc.
In the Battle of Berlin, couldn't the Russians "just" surround Berlin and starve it? Of course there would have been some German counter attacks but defending is much easier than attacking and if the encirclement was a bit outside the actual urban area, in open agricultural areas, behind a a river or similar, it is even easier.
In the two examples in the Pacific, it was easy to cut off the Japanese garrisons from getting resupplied. Other islands where left unconquered during the island hopping campaign.
The first objection is of course that the defenders were fanatic and wouldn't give up, but so what? Just let them starve for a month or two while you fly by and drop propaganda leaflets explaining the only death they can expect is not the glorious die for your leader/emperor but from starvation (and possibly by cannibalism from your comrades!) and their will to fight would decrease/will to mutiny would increase.
Time was heavily skewed to benefit the attackers.