I don't understand
What's so hard about building armor/mr as your first item and farming by tower if you're behind while top laning? I once had a riven build full damage against my Gnar and she didn't do anything, because I got ahead and kited her so she couldn't farm. Their LUX had to build tank because they were losing every fight and riven just "initiates" (She tried and failed) and dies instantly. What's so hard about itemizing to accommodate failure?