I personally think it all comes to exploring and implementing solutions for problems. There is always a cost associated with solving the wrong problem. Or implementing a bad solution for something that was not even necessary.

Sometimes software developement can devolve to, just becoming a trial-error approach instead of thinking about a set of strategies/problems to explore.

There is a good case that exploring problems further in specific direction than needed can help long term. But implementing solutions aimlessly is never a good idea.

I think this is what Kent Beck really means, critizing implementing something just in case because you might need it in the future.