Surrender has an S but I don't.

Listen I understand surrendering is bad and you should always have the chance to fight back and I understand that S's should be hard to get but why is it that when ever the other team surrenders @ 20 it basically demolishes my chance to even get a S- on a champion? It should not work like this. I am going for my S's on and I do well with him me my friend we destroy bot lane and we win a lot with just that but then once it hits 20 mins it just comes down to a lottery of problems like "Will the enemy team surrender or Will 2 people ( to be specific) and say oh do not worry I have the late game" IF the second option happens cool I have a chance for the S and a possible good game under my belt. But if the first option happens it is a gigantic middle finger from riot saying Fuck you for wanting that S. If anything In my thought is that if a person manages to make the other team surrender it should add a small boost to get an S not a large one that would automatically give you an S just something to maybe get you from a B+ to an A- but not enough to make an S- an S.