I can think of other routes to try besides PRG-ORK which would lead to a competitor response and an inevitable fare war with the much larger and bigger-pocketed FR. Wizz is not a large airline, and needs to choose routes it can operate profitably, and fights that it can win without inflicting too much damage upon itself. W6 should instead be trying to take over as much of NE's prime routes and infrastructure as it possibly can
Wizzair have already launched Cork-Katowice, Gdansk, Warsaw and Poznan with absolutely no response from Ryanair. I don't see why it would be any different if they launched Cork-Prague.