bug or riot made something

hello ..i just wanna ask something , so the question is if somebody conn to the server and diss after 30 seconds , why we cant do remake ? its a shit when u have a afk from the start and u cant do nothing , this happening pretty much everyday , and ofc i lose 10 games just because we cant do remake , or somebody go afk in the middle of the game , thats not even importat ..important is why we cant do the remake ? ty