Her True damage is garbage. Go actually look at a Vayne game's damage stats before you talk. It's 95% physical, stemming from Q or E wall knocks. The True damage is tiny as hell and actually her worst skill slot, and only on every third attack. Vayne's Q can hit 1700-1800 crits without enchanter assistance.
If you try to bring
into the equation, then yeah. The math changes a little, but so does it on EVERY adc, especially
who just regularly outranges all but about 25 skills in the entire game. (You literally have to suicide dive her and get shredded in the process, or stall out with skills like
's Q)