One of my first flights was to Rotterdam, I remember the apron being full of little Cessna's and Pipers. Something else today.
Well, the apron is needed for the Transavia 737s and VLM F50s, but GA at Rotterdam is alive and well. The Vliegclub Rotterdam owns about 17 planes (Pipers, Cessnas, Robins and a Diamond), the RAC has something like three planes (Warriors nowadays - their Diamonds are in storage at Lelystad due to an entirely different reason called Thielert), there's a parachute club, a few commercial operators with small planes for sightseeing and banner towing, and at least something in the neighbourhood of 25-30 private planes scattered around the F-apron and along the L-taxiway.
So GA at Rotterdam is still very much alive and kicking, and GA is in fact still responsible for the far majority of movements at Rotterdam.