As an acknowledgement, I understand you don't hold audio in high regards, so you fail to see an issue. But it is my hope here, to explain to you what people normally expect from a game and the effects of such. Remember, that everyone has different values, video games are built around those said values.
You are correct in some ways but not at the same time. I'll try to explain in a understandable way. Within a dungeon, raid or trial, every job will have their sound mixed in with other sounds, you would not be able to hear in fine detail the complete sound the job makes. That much is true, however every Job, while they do lose clarity in sound, always have a prominent SE that donates to this job being present and doing a particular action. For example, the Dragoon's 3rd combo which sounds like a passing jet, the three punches from a Monk's boot shine, the thunder sound from a Red Mages's Ver Thunder. I may not hear the impact the Dragoon makes at the end, nor the whoosh from the Monk's Boot Shine during the animation, or the casting of Ver Thunder before it fires off. But every Job's actions has a distinct and prominent sound that even in the midst of combat, can be heard clearly which adds to the feeling or the rush of gameplay.
But what defines gameplay? Mechanics, visual cues, audio cues, story? All of them actually. You see video game, and much of visual media, is built around 4 core pillars. Visual, audio, story, and mechanic (for games)/flow (for other medias), for this purpose, I'll only focus on video games and I will primary exclude story as it's not really relevant to this discussion.
If I were to make a game, I need to consider those core pillars. The story should be engaging, the visual presentation should match the story's tone, the audio presentation should match the visual presentation, and the mechanic should be intuitive/engaging that players would not feel off put. If I don't want a story, and instead I want a sandbox or arcade shooter, then I need to make sure the other three pillars are up to the task of player retention. These is the basis of what people expect from a game. Naturally these element heavily effect gameplay. Gameplay can be gauged by the players satisfaction and engagement to the said game, this is why people engage in "fashion wars". Being able to look and sound the part for your personal gameplay, effects gameplay. One example is that people tend to buy a game if a famous voice actor/seiyū is voiceing a character, it add to the gameplay that someone they like is voicing a character in the game.
For example,
If in my game, I have a Character who is visually and audibly stunning (think of heroes and their powers) but have poor mechanics, then I won't be able to retain players easily. But the opposite hold true however, If I had amazing mechanics but the character is visually and audibly repulsive (think of a 500lb guy with barf on his shirts, and the sounds associated) then I still would not be able to retain players. Now another example, I'm making a game about bloody vengeance, and the graphic style is baby chibi with realistic sounds, and good game mechanics. Even so my game may not sell all too well, I have great mechanics and audio, but visually it is not appealing to the game. Now lets say I have the same game, have a serious stylization, say "Max Payne" or "Hitman", but all the sound is from a kids show. Again it would not be appealing, this is because there is a specific interrupt that brings people out of the game. You yourself recognize this in some capacity with the chicken sound comment.
People hold the pillars in different orders and priority. Some people can play a game with a bad story or the lack of one, others could play a game thats in pixel 2D. Yet at the same time, there are also others who can not handle the lack off or a bad implementation of one of those pillars. Where you can brush off the audio issue, others can not, because it effects their gameplay. Sure, you can tell some one to play the Job regardless of sound because it has good mechanics, but thats like telling someone to eat teriyaki and mayonnaise roasted roaches, dogs or cats because they tastes good.