i do more dps on my level 8 mage than i do on my lvl 20 T12 ranger
also when u think about the different class abilities that rangers vs runemages have, what does the ranger have that is better or even equal to a mage, utility or dps wise? regular arrows are far worse than fire 2s, charged piercing is only a around 2k above a fire 3, and the difference is easily made up by the difference in fire 2 fire power, poison is worse than a frost dot which can stack 3 times, which is also worse than a afflcition, which can also stack, charged piercing is also only a tiny bit better than a ic\elance with icelance and fire 3 having 0 cooldown,
and yes, even our best utility the ranger trap falls behind compared to the polymorph, which once again has no cool down.
then besides those dps stuff, mages have other uses as well, such as manashield, decurse, pushback, etc etc
and finally dont forget about the skill cap
a ranger has a very clear max dps they can achieve while a mage is only limited by skill. i can spend 50 hours a day and never get any better dps, because i am limited while a mage can raise their cast time