Board Thread:General Discussion/@comment-28392795-20160711103207/@comment-25609885-20160718134818

The portal along with his journals are his life's work, he put so much work into building it that he couldn't just destroy it and take it apart, it would have one, made all his work and time spent in Gravity Falls a waste if he just destroyed them both and two, he might have disabled it properly once the journals to activate and start it up were far from the machine.