Fun and fairness do come in a large part come from the rules. Saying otherwise shows a lack of experience with TTRPG's. Rules facilitate the framework of the great hobby. Rules facilitate what kind of game it becomes. A Call of Cthulhu game is a completely different experience from a D&D game because of the rules, not the setting (You can have tentacle monsters in both, but the experience of the games vary because of the rulesets).
And yes, it is Larians campaign. But they did advertise that the game used the 5E ruleset. It would be like you inviting players to a game and advertising that you would use no houserules, but when the interested players show up, they get surprised by a whole slew of houserules that vary widely from the game they came to play.
Your example of houseruling potions is a straw man argument.
First of all. That's fair. The potions thing was a crazy oversimplification so let me be more concise.
When BG3 was announced, Larian Studios specifically said "BG3 is based on the fifth edition. We started by setting out the rule set very meticulously, and then seeing what worked and what didn't work - because it is a video game and DnD was made to play as a tabletop game. So for the things that didn't work, we came up with solutions."
Your acting and responding to an extreme. BG3 is built on a tweaked version of 5e. Some of the mechanics DO need fixing, so I agree that it is not perfectly executed, however Larian did not advertise that they would be ONLY using 5e rules. We aren't logging into the game to find they threw the rulebook in the trash and just did whatever they wanted.
