Explain me Business Model of L2 companies

Hi!

Layer 2 solutions are made for scalability purposes. By batching and compressing data, they improve the whole Ethereum ecosystem's scalability.

These networks are built by companies (Matter Labs, Offchain Labs, Consensys, OP Labs, etc.) that will eventually and progressively decentralize network operations.

But, as any company needs to make profits, I'm wondering what is their business model to make profits for themselves? Validators and Stakers make money for contributing to the network security. But what is the incentives for the company spending millions of $ to build the foundation of these networks?

For the moment, since most of these networks are centralized and operated by the companies' nodes but their part should progressively reduce as they will keep moving into decentralization.

Is their business model focused on next applications they will build on these networks? Or is it only focused on operating validators? Or is it just R&D? But I can't imagine investors would bring millions without having an idea of how they will make money out of it.

Thanks!