In many cases I can easily see how they could've designed things such that far fewer sizes were necessary, but they don't. I do wonder if it's an early form of "anti-right-to-repair" obfuscation? For some reason, I've noticed this "design quirk" far more in various import products than domestic ones.
It's also interesting to read statements like this:
The DSP and control IC's in new Sony recorders e.g. MZ-R90/91 cannot be removed from the board due to a packaging design in which the pins are mounted under the chips and cannot be accessed for de-soldering. When these chips malfunction they are impossible to replace and the whole electronic board must be replaced at considerable expense.
...and then realise that, 23 years later, a sub-$50 hot air station can easily do that work (I'm assuming it's referring to BGA packages.)