I mean, it was a bit of a farce that for 12 solid months the users who won diamond membership all happened to open their accounts Feb 5th and/or Feb 9th, but stopping it for that reason is odd. I just assumed noticing such a pattern was beyond chess.com even after I'd reported it to staff and also brought it to the attention of mods.
(these users also resigned many games to each other...)
For 2021 has chess.com stopped running monthly arena blitz tournaments where diamond is awarded?
For example this one was in December:
https://www.chess.com/tournament/live/arena/saturday-blitz-marathon--to-top-three-178335
But I can't find one for January of this year.