Here's another Bitcoin Foundation question... Why is this secretive foundation had so much turnover? And why are they not pushing for decentralized crypto exchanges? Centralized exchanges are an insult and outright contradiction of bitcoin and the blockchain!
The short answer is greed. In Bitcoin's early days a lot of people were willing to donate to them and they donated in terms of bitcoin, which has since risen significantly in price since they received the majority of their donations. By not being transparent, they can prevent them from receiving pressure to spend more of their money on the community.