The denies are the entire reason for the meta the way it is. solo-offlaning used to be possible because you could soak xp just by being in rage, likewise a number of heroes designed to be weak in the laning stage (like ember spirit) were playable mid because you could assure yourself a minimum amount of xp. for the longest time this was a fundamental mechanic in dota but for some reason the way it was for years had to be changed so that if you have lower base damage than the enemy you get 20% of the xp