His mistakes weren't seen clearly until almost 2019, when it became obvious 10nm was a disaster, and 14nm++++++++ was their only workable product.
We're still seeing it today as Intel has 250w TDP products competing with AMD 140w TDP products.
Semiconductors is a space where mistakes take a while to bit you.
Although as we've seen with AMD, it is possible to come back from them. With the right course correction, Samsung is diversified enough to tough things out. Didn't they have a massive turnaround sometime in the 80's too?
Seems not that far-fetched for Samsung to be facing cultural issues as well and that a company can be successful despite them for a long time. It seems like it's finally catching up to them as their competition becomes stronger.
See: Pentium 4