That was apparently their purpose back when we lost teeth more regularly - it's only with modern dentistry that they become a problem for being "extra"
It was not an intentional replacement or anything the dentist did. I had my back molars pulled and then a few years later while trying to start flossing again I noticed they were back and basically in the same position. I doubted myself for a moment if my memory was failing. Just such a slow long process.
I once went to a dentist and they told me they want to pull 13 of my teeth and give me dentures.
I knew they were in bad shape but this absolutely freightened me. Four of them were my wisdom teeth but I still thought it was nuts.
15 years later, I still have all of the 13 they wanted to pull.
I did lose two unrelated molars and the matching wisdom teeth basically slid into place replacing them. Then two root canals + crowns.
That experience turned me off dentists for a long time.
My current dentist is great. They do all they can do save a tooth and only extract as a last resort.