Let's face it: that amount would be low. The costs are around $10/month for Netflix, and less for HBO and Prime. People already complain about rising costs of streaming. Paying for another graphic shell over the same content won't be worth much more than 1$/month. Of that 1$, some, possibly quite a lot, will have to be paid to the streaming service. You need to offer considerable benefits for mass adoption. Suppressing promotions is not enough to achieve that, IMO. Perhaps a better recommendation system would be a more attractive option.

Note that the provider of this UI would be bound completely to the terms dictated by the streaming service(s). E.g., it might look interesting to have all your streaming services in one app, but Disney or Netflix or Amazon or HBO can simply forbid that option.