Do you really understand how Dash's privacy feature works? For a Private Send to be de-anonymized, someone would have to be in control of thousands of masternodes. The economic cost of pulling this off would are damn near incomprehensible. To say "eventually it will be broken" shows a misunderstanding here. You'd have an easier time just doing a straight up Sybil attack on a PoW chain (Monero included), which would be a hell of a lot more profitable than de-anonymizing a few interesting transactions.