Its like buses, they all come along at once.
So my prediction is, Wizz will mysteriously move the route to Gatwick in the next few weeks before it launches to avoid the direct competition with easyJet.
easyJet will probably do pretty well on the route, and once they become established in about 6-12 months they will move the route to Gatwick with higher frequencies and also cash in with higher yields from the South London airport.
I wonder when Ryanair will be joining the party with 3x daily frequency?!
It might be the case the Egyptian government is offering some very good incentives to serve Cairo from unserved airports that currently don't have a connection to the cities airport?