The point being that if 4chan users are (on the whole, anyway) too stupid to not spread JS viruses, asking them to not poll the servers so much is certainly a lost cause.
Getting the extension authors on board is probably the best option, because there's only a few of them, and they are not stupid. Stupid users don't have the skills to write broken extensions for themselves.
The only alternative would be (as others have said) to add auto-refresh JS to every page and thus bypass the need for extensions entirely. If the number of people who currently use these extensions is small enough, however, this could just as easily drive their traffic up because now every user on the site gets the same functionality without doing anything.
Getting the extension authors on board is probably the best option, because there's only a few of them, and they are not stupid. Stupid users don't have the skills to write broken extensions for themselves.
The only alternative would be (as others have said) to add auto-refresh JS to every page and thus bypass the need for extensions entirely. If the number of people who currently use these extensions is small enough, however, this could just as easily drive their traffic up because now every user on the site gets the same functionality without doing anything.