What is up with trains in Europe and luggage space?

I was in Europe for 20 days this past month. Went to Swiss, France, Netherland, Belgium via Eurail trains. What I notice is the luggage space above the seat (if and when there's any) won't fit a standard medium luggage! We ended up having to occupy seats and aisle with our luggage therefore reducing seating capacity for others. There are designated luggage space near the door but it's often insufficient and given the reputation of pickpockets tourists would understandably be wary of leaving belongings unattended. As I understand it, Europe is one of major tourist destination in the world so why would the luggage space be designed this way? I assume this is on purpose.