The point you are making here about valuation being a function of cash-flow is valid. However, it is not always associated with a business or equity. For example, cash-flow from interest payments on a loan is not equity. Additionally, while many cryptocurrency protocols are centralized and most definitely look like a business and security, this is not true for all examples or at all moments in time (i.e. centralization is a spectrum that is always changing and could become decentralized / not a security). From my stance, the focus should be on new economic activity and its value.