Currently, most functioning and public blockchains are monolithic entities. By monolithic, I mean a chain that handles data availability, settlement, and execution on its own. Now, there are some variations of monolithic chains, especially in regard to rollups on Ethereum and subnets on Avalanche that have modular components. However, those aren't modular blockchains in the most genuine sense of the word. Let's define what I mean when I say "modular" so that there are no misinterpretations. When I say modular I refer to the fact that the usually combined layers are decoupled. So what does this mean? It means that one of the three components of the chain is decoupled, so either execution, consensus, or data availability. This means that you can put the term modular on rollups since they only handle execution. While Ethereum handles everything else as a monolithic entity. In the case of Celestia, we can put the term modular on it since it only handles data availability...