Why doesn't AppleTV support multiple profiles?

I have a subscription to AppleTV+, I would like to allow my family members to watch shows on it without us stepping on each other's watch history, etc.

Since the service doesn't support multiple profiles I need to instead set up a "family share" so each user can log in with their own account (no other streaming service I use requires this).

Turns out I can't even do that without an apple device, which I don't have. Every similar service I use (Amazon, Microsoft, Google, etc.) allows me to set this kind of thing up on the account website. Why doesn't Apple support that?

Is this basic-level functionality planned to be implemented...ever?