Well here's an example of Mundo carrying his team with nothing but tank items. I had the only positive score on my team the entire game, which lasted 53 min. My teammates were
Gangplank - Refused to buy any survivability against a team with lots of gank ability. Didn't even buy lifesteal until the very end. Couldn't afford to get close enough to make use of his massive damage most of the time. Would usually get splattered when he tried.
LeBlanc - Didn't pay much attention to them. They just weren't very effectual most of the time. Their presence wasn't meaningful in general.
Taric - Suicidal. Did alright except for when he randomly begged the enemy to kill him. I wonder if he was having problems, because he would seriously play just fine and then... run without explanation or warning headfirst into the entire enemy team and die.
Mordekaiser - Complained constantly that we weren't aggressive enough against the fed team and kept dying because we weren't with him on his unannounced suicide charges. At least one death of mine was because I agreed to be more aggressive for him.
Was on vent with everyone but our one pub, Taric.
We won because the enemy was fed but unorganized and very greedy. They would kill 3 of us and sacrifice their potential push just to get the last couple. Fortify + Teleport + Mundo's epic innate stalling abilities helped as well. We held on, despite many proclamations (even by myself) that it was over. We also got really lucky with Gangplank getting the jump on Ash a couple times and two-shotting her in the middle of an otherwise lost team fight. Towards the end of the game, I was able to mostly ignore everyone but her and target her in team fights. Two warmogs + thornmail = she almost can't kill me without killing herself. I only need to hit her a couple times. I made sure to encourage the enemy to target me whenever I can afford to. Jax was really good with his ignite, and made this impossible sometimes.
Most games aren't this interesting because I'm with higher level players. If I'd done this well with people I normally play with, it would have been over a lot sooner and not worth posting. Or I would have not done as well and got shut down by equally high level opponents. This is why it's taken so long for me to post a Mundo game, despite bragging about it so much.