Ranged Carries Obsolete?

I've tried playing ranged carries ever since I first joined LoL and I enjoyed them for a time, but it doesn't seem to matter what my kill/death ratio is because the presence and contributions of a ranged carry are overshadowed by the abilities, burst, sustain, and crowd control of the rest of the team.

A ranged carry is the only class of champion that requires a babysitter because they've little sustain and because they've little to no CC. All champions need map awareness, but the squishy guy with the gun needs it more so than the rest of the team. They either need a constant escort to keep them out of trouble or they need to have some idea of where everyone is at and what they're doing.

A ranged carry is a hit and run role. They kill when the opportunity arises and then melts back into the shadows. They pick up the untouched farms for gold and slay the dragon and help take out nashor as needed. If it's safe enough and the way is clear, they come in to demolish towers with their insane AD and AS, but anyone can take out structures. A ranged carry just creates a shortcut that's easily substituted with a fighter. And that's where my big point comes in.

It seems to me that a fighter is much better at the job of a ranged carry. They've higher mobility, great sustain, many of them possess wonderful CC, their damage output equals or exceeds that of an ADC, and they can afford to invest in multiple defensive items without letting up the pressure on their opponents whereas a ranged carry needs to fill up mostly on offense.

I've seen many wonderful ranged carries and I cannot deny that it is satisfying to play the role well as I've done so on occasion, but a ranged carry is only as good as the team that's backing them up. As fun as it is getting more kills than the rest of my team as a carry, I also cannot deny the fact that it is extremely annoying to see that no matter how well I did, I still lost.