[No Green Spandex]

Wes and Jen weren't self centered jerks who would have risked harming the timeline for their own personal gain. Besides, changing your personal history like Wes did is a lot different then radically altering the timeline. Especially when Wes just lectured his Dad about it when he tried to use the antidote for Venomark for profit. Or the other times he was unhappy with his father for risking the future history just for financial gain. Even Mr. Collins realized he was wrong in the end.