The city I live in is in suburban sprawl mode right now. The main reason is apartments in city cost a fortune if you want reasonable amount of space. For family or hobbies or whatever. 1 bedroom apartment close to city centre == 2 bedroom apartment within city limits == 3-4 bedroom house with proper backyard and garage and everything just outside city limits.

this. A lot of Berlin's public transport infrastructure (a city that definitively sprawls in the suburb, compared to other EU capitals) was built in the late 1800/early 1900. Check density stats for Berlin.