It probably shouldn't count due to the nature of the "game," but World of Warcraft will never be surpassed by another game for me in terms of sheer hours "played." I put those two words in quotes because at some point the game became a job, and the hours played were almost like work or social time talking to friends. I haven't had an active account or played since 2020, so I can't check my hours; but I would estimate I had 200 days played on my main, 150 days on my primary alt, 50 days on my secondary alt... roughly 9600 hours total??
Outside of WoW, my next highest is probably a close tie between COD MW2, Counterstrike, Elden Ring, Ghosts of Tsushima, Oblivion, BG3, DOS2, and Skyrim. I can only focus on one game at a time, so I'll pick a game and play it exclusively for 6 months to a year.
The actual reason is because the church was protecting its assets from the priests. Back then, priests were very powerful members of local government and controlled a large percentage of the wealth in an area. If they could get married and had kids, their kids would inherit the wealth they accumulated instead of that wealth going to the church.