I suspect the confusion is more dependent on culture than language. Germanic (at least, probably other cultures as well) thinking allows an inanimate object to have 'ownership' of other objects (animate and inanimate.) I use 'ownership' to mean a relationship that has special importance.
Today's news
The events that occurred today 'belong' to today. Yesterday cannot claim 'ownership' of the events of today.
The previous class's students
Obviously, a class cannot actually own a student, but the students belong to a particular class--i.e. there is an extra-special relationship between the students and the previous class.
All of the examples in the original question were related to time ownership--a particular period of time having ownership of an object (physical or non-physical.) It's possible that the confusion is due to the way time is perceived. Germanic thought sees time as linear, therefore a given event or object can exist only in a single period of time. If an event repeats (eg. solar eclipse), it is seen as a different event than all other previous events having the same properties.
Another possible point of confusion could be the method of categorization. When considering 'vacations', what kinds of vacations can we have?
- Bus trip vacation
- European vacation
- Working vacation
- Summer vacation
- Summer's vacation
- Summers' vacations
- Last summer's vacation
In Germanic thinking, a bus trip cannot 'own' a vacation, 'bus trip' is a kind of vacation. In the same way 'summer' is a category of vacation, but 'summer's' vacation is that vacation-event that occurred during a particular summer.