No it does not, the past has multiple generations to describe while the future represents a new generation that cannot be defined in the plural until the next generation ends, maybe it continues indefinitely, only time will tell. It is a cultural language problem and generation in this context should be accepted in either singular or plural depending on the listeners interpretation as the essential meaning is the same--language is communication.
If you're talking about how generazione ends in the usually feminine plural E and then changes to the usually masculine plural I, that's just the way it works. When a noun ends in e whether it is masculine or feminine, it will change to i in the plural. There are many words that end in E and they can be masculine or feminine singular. Just like la tigre and Il cane. They would both change to -i in the plural.
Correct! In the Dutch discussions on "The turtles are animals" it is pointed out that in English "Turtles are animals" would mean all turtles in general but "the turtles are animals" refers to a specific group of turtles. And the Dutch use of the article corresponds exactly to the English.
I think Italian is different. With the article it is still referring to new generations in general. In fact Italian requires the article. For a specific set of generations Italian would use a word like "Queste ..."