It's a catch-22 situation or vicious circle, if you may. Everyone wants their original streaming service to maximize profits. No one wants to cross-license their content to keep it exclusive on their platform to prop it up. As a result, every streaming service to add new content must invest in expensive new content production. As a result, the subscription price must go up to cover these costs. Higher subscription prices lead to some loss of subscribers.
So this is why Netflix and, recently, Disney are trying to squeeze more out of their current customers without raising prices, such as going after password-sharing folks.