I think Spotify and Tidal can co-exist. Spotify is more suited for casual listeners, and Tidal is more suited for audiophiles. There's nothing wrong with that. If you don't want to pay for both, don't. If you think Tidal is a waste of money, fine. Nobody is forcing you to use it.
I don't think Tidal is obligated to offer a million exclusives, or force any of Roc Nation's artists into releasing an exclusive album/single. That would be a huge mistake, especially if someone like Rihanna did it. It's simply not happening.