Which is totally expected and explained by the fact that AOE2DE started off with a much more solid player base because people were basically playing the same game on Voobly and HD already.Unless I'm reading this wrong, you've got -19.5% for AOE2:DE after one month and -33.9% for AOE4 after one month. That's not similar, that's a significant difference.
Yes we would expect drop-off after release, but AOE4's player count is decaying at a more rapid rate.