(i.e. not thornmail/FH/randuins/sunfire/tabis/iceborn)
you forgot the chainmail, cloth armor, zz rot portal and the rest of items that give armor
if your math rewolwes around tanks without armor (and i cant see them geting much of armor when you dont allow them to buy it) then ofc that crit wins, since you are still fighting squishies
at some point lw just outpowers other purchases just because it allows you to get through that armor and amplifies your crit, its important on adc who unloads on enemy frontline a lot
you can argue
but try playing adc's without ever buying lw, and tell me how your crit is op when your crits will deal less dmg than you have ad just because enemy bought armor, probably one item will realy hurt you
and just for lolz i checked you, you had only one game of adc in current history, a caitlyn with lw in first item slot
arpen does not replace the damage, but amplifies it, thats why its actualy more potent than getting more damage in most cases, and thats why it is the tank melter stat not the crit itself, since arpen allows crit to actualy get to enemy hp pool