The US idea of Book Crossing, whilst having some resonance in Europe, hasn't really crossed cultures.
In the US, people read in coffee houses. In Europe, they converse. Equally, we might question the purpose of a book. If reading a book is an act of consumption (possibly more so in the US), then a book becomes disposable. If the book is an investment (possibly more so in Europe), then a book is bought to retain.
This indicates that a cultural nuance in one area (the US) may not be resdily replicated in another (Europe). Is it surprising that this book exchange in Starbucks Luzern is empty?