itch.io

The vast majority of games on Itch do not have an ESRB rating and will never have one. It does cost about $ 1500 to get one. That is on the lower side.

Which organisations would you speak of? Itch? The publishers? In both cases, that's not happening. Itch is a passive site. They only care for legal status in their home area. It says so in their tos. And the publishers here are decidedly not multi national corps with multiple branches in several countries. Companies like that do not need an indie ratings board. They can, will and often have to shell out the money for an official rating in whatever area they publish.

And in your example, both branches would be correct. Or rather, they do not even decide on that rating. They just submit the game to the ratings board in their respective area and pay for an official rating. The rating is only valid under the "jurisdiction" (for lack of a better word) of that rating. No one cares for ESRB ratings in Europe or Asia or Australia or wherever. If a game should be ok for 7+ according to one rating in one area, it does not matter, if that game is 17+ in another are - or even forbidden.

Just like your movie example. Outside of UK no one cares. That move is 12+ in Germany and for all ages in France. So yeah, that is actually an example for an item that is unrated/illegal in one country and rated for all ages in another country. And those countries can see each other's coasts on a clear day. For such a fundamental disagreement in ratings criteria one need not go to the other side of the world.

You can't have international age ratings. You can only collect information and calculate a rating estimate for a region.