PIVX needs to be accepted to exchanges with more volume to gain a higher market cap than it already has.
I think Poloniex will add it soon.
i am very surprised why they haven't added this coin already!
it is a good coin, with much better everything than most of the coins listed on poloniex, it is even said it i can compete with Dash and with PIVX not having the big Dash premine it gives this coin a big edge.
and on top of that the volume has been very big which is always the biggest criteria all the exchanges care about.
I think it definitely will get on polo. Maybe they are still setting up their severs or reviewing code to make sure everything is going okay.
Soon I bet very soon.