How does DeFi company make money?

Could you elaborate on the financial mechanisms and strategies employed by DeFi (Decentralized Finance) companies to generate revenue? Given the decentralized nature of these platforms, I'm curious about how they manage to sustain themselves without relying on traditional financial intermediaries. Specifically, I'd like to understand how revenue streams are diversified, if there are any subscription models or transaction fees, and whether DeFi companies also engage in yield farming or staking to boost their income. Additionally, are there any regulatory considerations that impact their profitability?