My son can’t write his own name. He’s 5 and has been at a steiner school for 1.5 years. He does however call me over to watch a sunset with tears in his eyes  “mummy it’s so beautiful”, and my kid’s a bruiser, so stopping to admire anything is big. Until kids are 7 the emphasis is on emotional intelligence, and the nurturing of ‘wonder’. At 7 kids brains are ready to read, so teaching them isn’t hard, and they’ll do it with emotion (Finland, anyone?)  By 9 kids are on par with mainstream reading levels, but yes it would be hard to move a kid from steiner to mainstream before that age. But are they disadvantaged? Oh no way!