Why does the Update Subscription endpoint not support updating the clientState property?

The clientState property of subscriptions serves as the validation mechanism for inbound subscription notifications.

For security reasons, the Update Subscription endpoint should support updating the clientState property, so that this property can be rotated without needing to create a new subscription from scratch each time.

I have created Feedback for this.

This is the endpoint documentation.

Why does the update endpoint currently not support this feature?