Question on a rune.

Gathering storm. So every 10 minutes you get more ad or ap depending on what you're building. With games that go from 15-30 minutes commonly why does this rune even exist? I'm sure you made this rune ideal for late game like after 40+minutes, but rarely do games ever go that long. Same goes for Overgrowth which is like +.2% max hp every 8 minions/monster that die near you.