The article by Silvia Sanides1 is an excellent piece, reporting on the important issue of "gray brain drain" from Europe, due to mandatory retirement. There is, however, an important caveat missing, which is that the system actually serves a crucial purpose of renewal. Although there are obvious exceptions to the rule (and those justifiably make the headlines), forced retirement contributes mightily towards removing otherwise unmovable tenured professors, whose contributions are minimal (and, in some cases, have been minimal for many years), if not detrimental. It is often, for younger professionals, the only realistic possibility of opening up career pathways, access to space, grants, implementation of curricula changes, etc. I know it's not nice to say this, but it remains, nevertheless, true.
Of course, Europe is not monolithic on this issue (or anything else, for that matter), and it ties in with the vaster question of tenure and evaluation of merit ...
