Here is the response I received from the Staralliance helpdesk:

The PDF timetable was discontinued due to the very small number of requests/downloads per month.
This is, of course, very unfortunate for those who enjoyed the benefit of the timetable, however we had to
make this decision based on the overall costs required to maintain this service.
We also offer alternative flight schedule solutions which are available on our mobile phone and tablet
products, which allow you to search any route served by any Star Alliance member airline.
Thank you for your patience and understanding.

I cannot believe what I read: what costs can be required to build a printable timetable and post it on the website ?