You're making the mistake of anthropomorphizing corporations. They're organizational structures, not moral beings. Were the humans punished? If not, that's a travesty. But it makes little sense to dismantle the corporations, which produce valuable goods and services.
Like the government, turn them over to different people.
Regarding treating the corporation as a single entity (versus treating it as a composition of ppl), their ideology and power still lives on. Krupp's (now part of ThyssenKrupp) owner was too ill to stand trial, though his son did, oddly enough. It still existed within the Krupps family, even after things had settled. It needs to be seen from both the composition lens and the singular lens to make sense
That sounds expected? I read Telford Taylor's book about the first Nuremberg trials. Of the 24 accused, three were acquitted. The jury (and even Taylor, who was the lead prosecutor) felt that some people deserved to hang and others didn't. Not everyone in a position of authority beared equal culpability for the war.
Maybe some Krupps were evil and others not; guilt by family association is not a thing in the western legal framework.