why do Wizzair operate so little from Prestwick
GDN and WAW remain but KTW and POZ were dropped as the massive influx of Eastern Europeans slowed down.
As for Ryanair, they have five based aircraft in the summer at PIK which is still a Hell of a lot more than when I was growing up. The core issue, alongwith many other FR dominated airfields across Europe is that allowing FR to use the facilities almost gratis allows no money for investment in facilities, so no ability to attract other airlines.
The old terminal at PIK is archaic but the rest of the airfield is thriving. Two runways, plenty pf parking and two succesful FBOs with traffic variety other airfields would die for, all count for little on the balance sheet as so much is geared around FR. Tis a tricky one.