Sorry, my mistake. So two in 15 years.
Wizz Air can compete at the moment, because of their low cost of workforce, as having people based predominantly in Eastern Europe allow people to pay almost no tax due to lax legislation as well as almost no oversight of local tax authorities. Add to that the extremely transparent Swiss tax arrangement, and you see why opening bases in Western Europe is difficult for them.
Because if they want to attract people to fly for them in the West, they will have to offer the same (or better) net salary that they pay in Eastern Europe. But with real taxes and not just 0-5% Swiss tax and some mini social contributions, this will increase their costs by up to 50%.
There is no capacity in Eastern Europe for 300 additional LCC aircraft.