I really wish I was so good that I could quantify how tankless / initiatorless games work.
I just finished a game where everyone on my team was literally a squishy girl. Irelia (me, and I didn't buy tanky items), Janna, Akali, Nidalee, and Teemo (yes, he's not actually a girl...). We got pretty hammered in our lanes as the enemy had two tanks, a burst caster, and two physical deeps. They could towerdive us nonstop. When we lost all our front towers though, everything changed. It's as if the towers were holding us back.
The enemy were always stuck together but somehow, we could always poke and kill one person, then escape without damage. I'm not sure how to describe it.
Mrm... it's like Nidalee and Janna would do their crazy harass. Then I'd look for whoever took the most damage and dash stun / slow. Immediately Akali follows and kills the stunned enemy. Then we all run away as Janna CCs everyone chasing with her tornadoes and her ultimate. I really don't know how it worked. We'd do that repeatedly, always pick off one or two people so they could never have a proper teamfight and we'd always get to push the towers since they'd be missing people either due to the fact that they had to bluepill from the poking or were just dead overall.
It was LoL guerilla warfare. It was so easy to ambush them as we had wards, Nidalee traps, and Teemo shrooms EVERYWHERE! We could see the entire map.