I'm a little late to the party but ultimately the skill of "getting carried" I think mostly is about being able to not tilt, but also know how to play from behind. It can be difficult for people to keep a positive mindset when they fall behind, so being able to take it in stride and be able to tell when to do what is an extremely valuable skill to have.

Let's say someone falls behind as say, a midlaner or something, and they're playing someone who is extremely gold-reliant. It can be easy for them to think "oh it's gg I'm not carrying the game" and they might be so focused on what happened in their lane, they're blind to the fact that their other lanes are doing well and overall their team might be even or even ahead of the enemy team. So, they might tilt and try to surrender so they can "just get out" and have a negative attitude and make really bad calls and put their team in a really bad position.

But, being able to "lose lane gracefully" is something that can be done, and being able to tell what the limits of your champion vs the enemy team and the limits of your current items and levels is really, really important. But, in regards to a Soraka (and oftentimes other support/utility champions) they can carry their own fair share in another way that's not really acknowledged in the game. Sometimes it's easy to just look at damage and forget about wards, healing, and individual plays and it can be hard to really show that on a stat screen.