Why does Rumble look good in the late game these days?

  I used to think Rumble was a super strong laner but fell off hard late game, but lately it doesn't really feel that way. He's still a beast in lane, but the whole "he's trash late game" thing just doesn't seem true anymore. His ult is a massive AoE nuke, his Flamethrower is also AoE so it's great for following up on your team's CC, and his Q is a ranged slow that helps seal the deal when you're ahead. If you manage your heat well, he actually feels better than Garen in the late game. But... I'm not sure when you're behind. When it's even, he feels solid..?