Yes ...... the activity of alot of older well established players has declined due to several factors, not the least being the "Game Improvement Debacle" (hereafter referred to as GID) , which you missed by being absent ...
GID frustrated and angered many players (and still does to this day), so much so that forum threads were running rampant and springing up willy nilly all over the forums about glitches that were creating more problems, and fixing those created more problems, etc. etc. etc. ad nauseum ... you will notice the differences when you begin playing again.
Good luck ...