I've even heard of cases where a carbon bike frame (itself worth thousands) was cut so the parts could be stolen. But you're right, the solution is a beater bike with a big lock, and if you have a nice bike, keep it indoors and never leave it unattended for more than an hour.
Even a beater bike is no solution, I parked my old beater (a rusty old department store bike) at the train station, and still had the seat stolen. It was bolted on (no quick release), so whoever took it apparently had tools.
So I stopped riding to the station until I got a bike locker.
Bike lockers are pricy in cost and space (compared to nothing, not compares to parking garages) but the only meaningful solution. Perhaps bike rooms with human attendants could work, and solve the job loss of creeping automation too!
