Sorry but I can't agree with you here. When Monero still allowed mixin 0 transactions almost nobody used the privacy-enhancing transaction type. The same goes for Dash and it's DarkSend, or Shadow's ring-signature side-currency - all virtually unused.
Thus X grows at a rate that is useless for its intended purpose: getting lost in the dust of millions of others.
But to make matters worse, ZCash is grossly irresponsible by not making private transactions mandatory, as people will use t-address transactions and think they're safe. Pools pay out to t-addresses, exchanges only accept t-address deposits, and lightweight clients will all end up being t-address only as it's the quick win.
Claiming that it's "just an experiment" is not acceptable when people's money is on the line, at best, and where their lives might hang in the balance, at worst. The disgusting and dangerous approach taken by the for-profit US company behind ZCash, that of fast-tracking the launch of massively immature technology due to investor pressure, is something that should lead to grave consequences for them because of the nature of this technology.
I greatly respect the work of Ben-Sasson, Green, Garman, Miers, et. al., but even they have been complicit in the rush hack-job that is ZCash. We would do well to consider what advantage a nation state attacker would have in encouraging adoption of this immature and likely broken system, over alternatives that are FOSS and have prolific contributor communities.