I think vacations help mostly in the sense of "I just need to get through the next two months". That may help as a coping mechanism for burnout, but doesn't stop it.

And of course if you have a job that perpetuates cyclical or chronic burnout, going on vacation just means that you come back to work even more buried in things that went undone.

Or you sacrifice having a true vacation and still commit to working part of the time you're away.