My hot take is that you don't actually want fewer streamers. As it stands, pirates benefit the most from content wars because the services are paying more to produce shows than they are receiving in subscriptions.

The obvious losses are legacy content and access to it. I don't know that there's a good solution. A streaming service benefits most from surfacing content that will keep you on the platform, meaning either a modern series with promised future seasons, or older content that's still popular. Any old obscure media is going to lose money for rights holders on a $/stream deal because they could potentially make more $ from a single physical media sale than any amount of streaming would net them (if it's $/stream, and only 2 people stream it, that's very little return). And nobody subscribing to these services is going to shell out more money for specific titles because to them, that's why they're subscribing in the first place.