Conti Sport Contact 5 completely worn after 18,000 km!!!

Hello, it can be quite that the topic has been addressed more often. Nevertheless, I would be very grateful for a quick answer. I drive an Audi A3 Limousine 2.0 TDI with front drive and hand-operated. I am a commuter and drive 150 km a day. The vehicle has now run 18,000 km and the front tyres are worn almost to minimum profile depth. At the back are still about 5-6mm. Continental Sport Contact 5p are mounted. The tire size is 235/35 R19 Y. I I have a sports suspension with Magnetic Ride. Is it normal for the front tyres to leave so fast? I drive 90 % motorway with 110-130 km/h. Basically I’m just rolling. On average I consume 5.2 l diesel. What I noticed recently: If I take the gear out of the car on a slight gradient, the rolling resistance is so strong that the vehicle loses speed. Is that normal? Thank you!