In some places in the world (like Pakistan), it is common for upper middle class people to have custom cabinetry in their homes. Usually, during house construction, the carpentry team shows up with the necessary cutting machines. Usually a back of pickup van is sufficient.

Everything is cut from full sized boards as needed on site and installed right there.

It works because wood working machinery is fairly cheap, not heavy and works off standard electric power.

And labour is cheap.

In other parts of the world, you standardize cabinetry sizes and just build for that.

Then a long list of providers offer cabins that fit.

Custom sounds expensive and hard to replace when needed -- what's the upside?