Samurai Quack: So, my defeated adversary, how mayeth I escape this here taco stand and returneth to whence I came?
Tartakovsky: Only the evil tyrant wizard, the master of masters Ah-Choo, has the power to send you home. Or you could just use this time portal right here. But then, of course, you wouldn't be able to defeat Ah-Choo and end the oppression of my people. -Where are you going, noble champion?
Samurai Quack: So is there a button I gotta press?
Tartakovsky: Please, you must battle the evil wizard! That time portal is just a prop. It's supposed to introduce a moral conflict.
>>117493708Because if Jack had just returned to the past at the first opportunity it wouldn't have made much of a difference because the future was going to be rewitten anyway. Most of the series is basically pointless.