Maybe. Maybe the fighter can't convince the dwarf to drink the ale. Oh well, we tried. There must be some other way to get that info, though, let's look around.
Maybe the fighter can convince the dwarf. The cleric wants to cast his spells so the fighter and cleric goes off and comes back with the buffs. Maybe the dwarf doesn't even know. Maybe the fighter is too proud to accept the buff. Maybe the fighter is a dwarf himself.
Maybe the fighter can offer a bribe and assures the dwarf the other two won't be in their way. Maybe that fails. It's the nature of the game. We don't play the game to never lose. It's fine to want to maximize success, but the game isn't about never failing.
Sometimes, nothing you try works. Now what? Well, we keep playing. Because there's still much to do.
And all of that stuff can be done by the paladin, or the sorcerer, or the bard, all who have potential mechanics to back them up, while the Fighter is solely at the mercy of the DM and a potential flat roll.
I agree, players play and be clever, but saying "well anyone can try to climb the mountain" kind of ignore the point of one person is likely to fall to their death, and the other has a climb speed so it is exactly the type of thing they are supposed to be doing.
But I want to make it clear that if a DM isn't on the player's side, the campaign and group is going to struggle alot. They'll want to change characters or they'll check out during big moments or they'll not show up as often. That's what really sucks. It doesn't matter if the book gives martial classes every social and utility ability in the world. I mean, it would matter but it wouldn't change the fact that the DM isn't compatible. Eventually, the books will end their guidance and the DM has to step in and say something. The DM is probably the sole decider on whether you enjoy your game or not. The mechanics matter, please don't get me wrong, but the way the mechanics are implemented will always be up to the DM.
But what about the people who do have the mechanics?
This is the problem. Let us say the DM lets the fighter just be charming and work the social scene, because this is a rare dice game. Then what was the use of the Bard putting their expertise in persuasion and playing a glamour bard to charm people? The fighter is doing their job, with no mechanics, so why invest in the mechanics?
It is a bit of a catch-22, either the people who invested mechanics into it feel like they wasted their time, or the people who don;t have the option to invest in mechnics feel left out.
And if it was an easy problem to solve, it wouldn't come up in every single edition of the game.
I suppose this really depends. IME a DM should only be calling for a roll if there is a consequence for failure. If it is simply moving the story along, there shouldn't be any rolls IMO.
If there are consequences, and you are non-proficient with a CHA 10, why is your character making those rolls? Unless your PC is the only one there who can even speak, someone who is better at it should be doing it.
Now, can your STR 10 Wizard open an unlocked door to move into the next room? Of course, and no roll should be needed. But does your STR 10 Wizard try to break open doors? No. Because your STR 18 Barbarian is better at it. Your wizard opening an unlocked door is your CHA 10 PC moving the story along, the wizard trying to break a door down is when your CHA 10 PC should be making a roll.
If your DM is making you roll for things you really shouldn't need to roll for, I would certainly point that out, but otherwise if you want your PC to participate more when consequences are an issue, build your PC accordingly.
I'm curious why
@Asisreo liked your comment when this goes exactly against what they were saying. The bolded part is exactly what we are saying, and exactly what he pushed back against.
And there were consequences. Failing the mission. The scenario I am thinking of in particular involved us sneaking into a party. We split the group, half going in the front and half going in the back. I was in the back group with a disguise as a chef, which my character was a chef, carrying supplies for the kitchen.... and I failed the roll because I had a +0 mod. And that would mean an alarm would be raised, and we couldn't get in, and we would fail the mission, because we were actually meant to do the more important part.
So the DM had to give me retroactive advantage (play by post game, so the other players with me hadn't spoken up for the help action and he had an NPC do it) to barely pass... and I promptly did the exact same thing five minutes later when we encountered a second set of security.
And the thing that was making the whole situation worse, was that we knew we could fight and win. We could have slaughtered everyone in that building and gotten what we needed, because we are decently high level and we were at full strength, but we had been specifically ordered not to fight anyone.
But, to your point that if I want to be involved in the consequential social scenes, I should build for that, there is a problem. Most classes don't get anything to help with that.
Barbarian, Fighter, Ranger, Druid, and Monk get nothing to really affect social scenes. Wizards only get by because charm person and other obvious magics, but they usually can't do anything either. That is half of the classes. And, if they aren't viable for building to be involved in both combat and social situations, well, we just end up building more Paladins, Warlocks, Bards and Rogues who can do 2/3rds of the game instead of 1/3rd
Unless the Bard speaks Dwarvish or has Comprehend Languages as a spell known, he might be just as useless as the Fighter in that situation. The Dwarf Ranger would be the principal interlocutor in that case, even if he has an 8 Charisma
And again, if the dwarf can speak common, like most dwarves do?