Feels like this article buried the lead in order to prioritize a complete click-bait headline lure. Player use has most likely fallen off because most of those early players have finished the main storyline and moved on (or back) to other games. But I guess that blinding flash of the obvious doesn't draw eyeballs...
While somewhat buggy on PC, none of the bugs I've encountered where at all game breaking, and the positive reviews on Steam are no mystery. It's arguably one of the most engaging FPS/RPGs to hit the market in the last year. It's easy to see that there'll be a huge market for premium DLC, which will also drive new players into the original game, once CDPR gets the rough release polished.
The bigger mystery is how CDPR is going to position that DLC given the way they chose to craft the various endings to CP2077. Those design choices, btw, likely contribute to the significant player falloff numbers, much more than the headline cause you chose to run with. And so what -- it's a boxed game, not the kind of subscription MMOG for which peak simultaneous is an important KPI for gauging ongoing success.