"Eyes On" is the only measure that really matters, for Amazon. If the ratings are good enough, regardless of the audience scores, more will get made. No, Amazon isn't in competition with Shanara (it was cancelled) or Game of Thrones. They're in competition for subscriptions. If their aggregate programming is enough to keep building viewership, then they'll keep going with it. If a property doesn't meet those viewership goals, which typically will involve growth rather than retention, then it'll get the axe.