Why don't newborn kittens retract their claws?

Kittens do not retract their claws until they’re about a month old. Until then it’s best to keep your fingers away from them because they’re pretty sharp even if they’re tiny.

Do they not retract their claws before this age more because:
a. they don’t have the strength to
or
b. they don’t know how?

I lean towards a much more than b. Human babies wouldn’t be able to walk at 3 months old even if they theoretically knew how because their leg and back muscles aren’t strong enough to support them yet - it seems likely that the muscles in a kitten’s paws need time to strengthen too.

I could of course be completely wrong. Anyone know the truth?

Ever see a kitten ‘knead’? It’s how to get mom to produce more milk.

Those are ‘milk claws’. just as they have ‘milk teeth’.

Presumably, the claws maximize milk delivery.