New Crafting system

I recently played a match as Nautilus support. I won 0/0/14 and got a C+, my adc went 14/1/3 or so, and got an S. I was wondering how the system is organized to allow for support mains to get chests and crafting items on the same level as adc's. I dont take kills, I dont take cs, and I dont get THAT much gold as a support- and im not supposed to, right?. So if these are the ways the programming measures performance, how can it be fair for supports? I understand that the ranking D to S has to do with percentile performance, but how can I get better than a perfect game and high assist rates?

On a side note, I Urgot main as of about a year now, and was wondering if there is anything, anything at all, that I can do to get an Urgot butcher skin. It would mean the world to me to be able to pay even excessive amounts for this skin.