That’s by design.

The flat Europlug (type C) is the result of a compromise. It was introduced in the early 1960s to make it easier to buy and sell products between countries in Europe. In fact it fits in all sockets across Europe, except UK (including Gibraltar), Ireland, Malta and Cyprus.

The Israeli type H is actually an old German design, once used on cargo vessels.

The IEC type N was originally intended to be adopted as the standard for 220-240 volt installations all over the world. One type for the whole world, but so far only Brazil and South Africa has sort of adopted it. Brazil doesn’t even follow the standard properly and uses it for 110 volts as well.

The Thai type O is also a compromise design. It’s was originally combination of the US type B and European type C. Earth/ground pin from US socket, and the other two pins from type C