Up to the point of rivalry? I don't think it will. What's the possible rival of Ethereum is Binance Chain. But so far, most of the projects are still made through smart contract of Ethereum. If they want to migrate, they can easily do that with other chain and even in NEO.
But, I've rarely see projects that's been built through NEOs chain so I don't think that it will even come close to what Ethereum is getting. It is unlikely but not impossible.