That game has over 130 mythological characters, and nearly 20 pantheons. Most other mythology-themed games only represent overused pantheons, without representing the less known ones.
Honestly, it’s a Western media thing. Pretty much the only mythology most of us English speakers are taught is Greco-Roman. In past decades, efforts to branch out were often shallow. Things are getting better, there’s more stuff coming out drawing from indigenous or African or South Asian mythology or whatever. But it’s taken some time.
Video games have been mostly made by white dudes, after all. They’re exposed to white dude stuff.
On the same note, the target audience is mostly white dudes. It’s a lot easier to sell them the fantasy of playing as / fighting against Thor, Zeus, or Hercules than it is to get them excited about some character they’ve never heard of and can’t even pronounce the name.
God of War originally was Greek; but the newest one has fucking everything. Greek, Roman, Viking, etc.
A lot of roguelikes have pretty much every mythological creature plus their own made up shit.
Age of Mythology was built around this idea.
Path of Exile has pretty much everything by now.
Money.
Because those characters dont fit the themes of most games.
Some games, like those in the FATE series, can make use of those kind of characters because it fits the theme. Other games can’t, since it wouldn’t make sense.