So the randomness providers secure the deposit of their own randomness. The circularity of the system means it won't work in practice. RANDAO is secured by the proof of work miners.
Actually, this kind of "snake eating its own tail" loop is exactly how cryptocurrencies operate. For example, proof of work blockchains secure themselves by creating mining incentives with money that has value because it is secure.
It works because the system can regress over time, e.g. value at t=n can be used to secure a greater amount of value at t=n+1. (Although value needn't be strictly increasing for system to operate; if value decreases, so do the security requirements)