Why does Fireball do 1/4 of Incinerate's Damage?

Started a Sorc for fun, got Fireball up to level 5 just for enchantment purposes while levelling and looking at my skill tree I am just now seeing why my damage has been lousy.

At 5/5 as a 46 Sorc, my softball is hitting for 396 damage.

Incinerate on the other hand, does 701/second ramping up to 995 after 2 seconds at just 3/5.

What the hell ? And yes I know fireball has a bunch of uniques and whatnot but that still seems wildly disproportionate.

Incinerate is overpowered in the early game due to a series of increasingly ridiculous buffs it has gotten to try to make it usable in the end game. It scales very poorly for a number of reasons, which means they had to end up increasing its base values to silly levels in order to do this. That’s really all it is. Consequently, it’s a great leveling build now, probably one of if not the best one we have, but it falls behind Fireball in the end.

interesting right?
damage with fire and damage with burning are 2 different thing.
combustion and endless pyre works on burning damage.