If Dash would integrate mandatory privacy like Monero did, then it could easily reach the value of ETH.
That's a curious viewpoint, since Monero itself (presently $96.56 at Coinmarketcap) did not reach the value of ETH ($288.53) despite having "mandatory privacy". Meanwhile, Dash ($340.27) has much higher US$ value than either, which suggests that the market is relatively comfortable with its present trajectory. Even if your view is based on market cap rather than coin value, Monero with its "mandatory privacy" is far below ETH so adding "mandatory privacy" to Dash would seem unlikely to propel it "to easily reach the value of ETH".
Monero doesn't have the community size but it has the privacy.
Dash has the community size but it doesnt have privacy, but it is at least decentralized (if this masternode thing would sort itself out eventually) and well organized.
ETH is neither private nor decentralized and it's almost to say pretty unprofessionally organized especially in the DAO fiasco, the ETH Foundation has overwhelming influence and I don't think that is good for a project of that magnitude.
-Fee. Did you saw that monero have the highest average fee per transactions?
I guess privacy has it's own price too.