I recall, YEARS ago, attending a wilderness survival class taught local to me. It was a 3 day course, as part of a 40 hour long training course we took for our local S&R team. The first night, one of the first things the instructor said, which sort of stuck in my head, was that there were two things you cannot easily make in the wilderness (mind you, I live in New England); rope & a knife. Everything else can be found or manufactured.
That didnt really stick out in my head until we started making cordage from nettles-it takes a LONG time, and doesnt function as good as real cordage. Fortunately, I always have 550 cord as bootlaces (holdover from the Army days), and I cannot recall the last time I didnt have a knife on me (flying being an exception).
I thing learning to improvise goes a long way in a survival situation. First & foremost, it keeps you ENGAGED IN STAYING ALIVE. If you are stuck for more than 24 hours, you have a LOT of downtime. improvising can help fill that. And, you are actively engaged in staying alive, and getting found. Of course, this is taking into account you arent hurt, or part of a much larger disaster. The latter would present far more opportunities to improvise-but, I would rather avoid that, than participate in it