Actually peercoin was first coin that used pos. It was a hybrid pow pos. Nxt was first to use just pos. Nxt launched at the same time mastercoin ico launched. Which led to counterparty and at same time  a mastercoin consultant named vitalik spun off some realizations from his mastercoin work and had an ico for his idea of eth.

Back to nxt. Nxt is being used as a distribution network for the ardor chain and soon the ignus childchain snapshot. Current nxt devs are set to discontinue work on nxt, and instead support the business minded network of ardor, of which many child chains can be created.

Nxt the network will most likely survive, however it appears the value is passing to ardor and ignus. Id image a price drop folloed by a long accumulation period by some whale and then new dev team and big increase.