I think you misunderstood GP. My take on their point is that when a question from 10 years ago about a C#/SQL issue has a top answer with 300 points about using a library that’s 12 years old, but a better answer with Linq from this year only has 4 points, people are probably going to either go with the 300 point legacy answer. A decaying function can implement relevancy.
I think it’s a good idea!