It has already surpassed both Dash and Zcash in value market cap wise, the value per coin is much more tied to supply, not development. So Monero can be better, have a bigger market cap and still not necessarily surpass the value of Dash/Zcash. I think all three coins have some good privacy features but out of them, Monero is slightly ahead of the curve. The developers behind Monero are some of the best in the business too. But again, that doesn't mean to say it should be worth more than the other 2.