The privacy stack is coming together. Smart contracts can now operate on encrypted inputs and return encrypted outputs so validators never see plaintext. Shielded pools mix deposits into a common set so withdrawals can't be correlated back to specific deposits. The remaining gap is the default. Every privacy primitive requires the user to opt in, which keeps anonymity sets small. No major chain has flipped the default at the wallet and protocol level, and that is what could decide whether onchain privacy goes mainstream or stays a tool for users who already know they need it.(Delphi Digital)