Why don't region specific pokemon have their own national pokedex number?

Garahs

The pidgeot line has their own national dex numbers, so does the staraptor and other bird lines. So why do we have multiple different types of rapidash, ninetales, etc., that take the same national dex number?

It's very irritating for organizing a living pokedex in Home.

puplover1118

Because forms aren’t considered separate Pokémon. Stereotypes like the regional birds don’t include the same Pokémon just as a different form, but as a whole new Pokémon.

Nadjie_

Honestly? I just store those pokemon in their own "forms" box. Leave the original pokemon in order.