At what point was this a winnable game for me?

The part where you didn't buy sightstone

That poor Fizz lol. The enemy team was very snowbally and early game heavy while your team was... Something. I'm not familiar with new Galio enough to classify him as early or late but this was probably a case of being out picked. Course with an Akali and Shaco as their first two picks, presumably, I would have instalocked in Nautilus or other CC heavy support to deal with that. Lulu might not have been the most effective pick in that comp.

Why max E? Wouldn't W be better?

I would need to see the actual replay to be more certain. But I'd say you had a chance to come back all the way up to the 11 minute marker.

Until the the gold difference wasn't so substantial that your team fighting should've been on pretty even keel. I do echo the sentiment that a Sightstone might have helped avoid some needless deaths early on.

Additionally, I notice a heavy amount of the kill spread is oriented in top lane. If that is where they were focusing their attention a quick roam up to drop some wards could've helped as it seems that lane was the grief-focus.

They took an inhibitor at 12 minutes. A sightstone isn't doing anything at that point in the game boss. Lulu was an early rotation pick which is pretty standard at high elo. So is E max as it is your main source of utility poke/ shielding, especially with a AD that isnt going to scale well off of attack speed. Fizz died at lvl 2 with summs, teleported back to lane and blew his summs/died to a gank and then died again at lvl 5. LOL