That's not true you can have complete end to end encryption. By default. iCloud is not encrypted, but you can encrypt it and nobody but you can get access access your data.
It's off by default because if you lose the password then you lose everything and that's a support nightmare.
Can and do are two vastly different things. The assumption that data privacy can only be accomplished by no one having any access to data is ridiculous.
Of all the companies that exist right now, apple does a fair bit of work regarding data anonymization and access restriction.
It's off by default because if you lose the password then you lose everything and that's a support nightmare.