Here and elsewhere, I disagree with you about the question of awarding merit to old posts. The archives of this forum contain a hidden library of knowledge, especially in the Development & Technical Discussion section. Awarding merit to old posts helps highlight them; where the authors are still active, such belated recognition also has direct utility. The first merit I awarded to any post older than a month or so was for
the post which first brought me to fully realize the problems with DHTs, and why Bitcoin does not and will not use a DHT. I could not exclude such classics from consideration for merit awards.
As an abstract concept, I probably agree with you. However, you have to consider that merits and sMerits were created to solve a current problem, and that is the pollution and deterioration of the forum. To combat that you have to influence new posters to rebuild the forum. The past is the past, but we need to grasp the opportunities in the new future.