Policies do a great deal to determine elections - American political parties are more polarized by policy now than they've ever been. It only seems otherwise because there's a lot of people who don't consider opposition to their policy objectives legitimate, and thus diagnose it as cooked-brain syndrome rather than attempting to understand and compromise.
People's policy preferences are downstream of how cooked their brains are. So it's not really policies that are determining it, it's the fact that their brains are cooked through constant exposure to bad things. If their brains are uncooked through constant exposure to good things, then their policy preferences will also change.
Now I'm not sure what we're talking about. If you postulate that brains can be "cooked" and "uncooked" in response to new information, doesn't "cooked" just mean "persuaded"? I definitely agree that my policy preferences would be more dominant if people spent more time ingesting the good arguments and good evidence that convinced me to hold them.
That's fair -- "cooked" does imply an increase in entropy that can't be reversed. I think it sadly is irreversible in some people, but many others can be brought back (you're already starting to see a backlash to Trump).
Being exposed to the arguments over and over, repeatedly, probably matters more than their quality. That's what I was going for with "cooked", since "persuaded" isn't quite the right word for it.
