What is the most common business model?

Excuse me, could you please clarify what you mean by "the most common business model"? Are you referring to the most prevalent model across all industries, or perhaps within a specific sector such as cryptocurrency or finance? Understanding the context would help me provide a more accurate answer. For instance, in the world of finance, the fee-for-service model is often prevalent, where financial institutions charge clients for the services they provide. However, in the realm of cryptocurrency, the decentralized nature of the technology often leads to novel business models, such as those focused on mining, trading, or even the creation of decentralized applications. So, could you please elaborate on the specific industry or context you're inquiring about?