There isn't one. As far as I know, no one really knows for sure how they bypass all these paywalls. (Most credible theory I heard: They actually just pay for the subscriptions.)

I think there are multiple hurdles that make a new competitor very unlikely.

The first one is money. You need lots of it to run such an operation (servers, IPs, paying to bypass all these paywalls, etc.).

The second one is the legality, as no one wants to be hunted by the FBI, especially not for running a website that is also losing money.