[2020] Can Someone Explain Mages To Me

Like why are they very strong early while also scaling so well into the late game. Why do they have both CC and high damage in their kit. Why does protobelt only cost 2500 gold why is Zhyonas a thing it seriously has to one of if not the most broken item in the game.

Why is it so easy to get armor into a normal build but so hard to build MR. At the same time why is it so easy to build spell pen. It results in mages basically dealing true damage even to tanks in some cases, please explain how that is fair and balanced in any way. I've even seen mages played bot in some games, how is it fair for them to be viable in literally every role.

Either mages need reworked/heavily nerfed or Marksman, tanks, and bruisers need big time buffs to compete.