Will there be need for Layer 3 protocols?

As we all know, there's been layer 1, 2 and 0 protocols and each layer with its own peculiarities. 

Layer 1's tackle scalability issues. layer 1 solutions can facilitate increased block size over the base protocol. As a result, the blockchain network could process more transactions in one specific block. 

Layer 2 protocols on the other hand, were created to help layer 1's to be better blockchains. With the introduction of Layer 2, blockchain transaction speed tops up, and this in some way leads to reduction in has fees. 

Layer 0 protocols help to implement proper interoperability. There are very few layer 0 protocols out there like LayerZero and Analog. These guys prioritize on interoperability possibilities between different blockchains.
So, what do you think Layer 3 protocols will come to fix. What function will they bring. According to Buterin, Layer-3 solutions can also be built around non-EVM platforms and Layer-3 solutions could be implemented in privacy-focused chains by utilizing zk proofs to submit private transactions to Layer-2.