In 2018 we will see x10 for Pivx. One of best projects.
I think you will see close to $10 before 2018. Once the zerocoin implementation is release, the price will go up.
Then a masternode would be worth 100.000 $ ... guess some will then sell off and the masternode count will decrease .... not many will pay 100.000$ to install a new masternode ....
If that would happen, rewards for running a masternode would also be x5.
If the masternode count would decrease, a simple update to run a masternode with 1,000 PIV would fix it.
i dont thing 1000 PIV ist good idea ... existing MN owners would not like that ... you would have to host 10 nodes insted of one ....