They really aren't needed though. Ability checks can resolve tasks without skill or tool proficiencies attached. I believe older editions of D&D worked fine in this fashion.
I've already said that any given skill can be done away with and just have stat checks. If that's how you are meaning that they aren't "needed" then I've already agreed with that pages ago. So let's not argue semantics. You know (at least by now) that when I said skills were "needed" it wasn't meant in the way you are trying to frame the discussion because I elaborated and explained exactly why I thought skills were needed and that was to add more granularity to important abilities in the campaign setting.
Since campaigns vary in terms of content depending on table preferences and DM, then doesn't that argue for a more exhaustive list of skill proficiencies that a DM can tailor to fit what he or she is going for?
I actually don't think an exhaustive list is needed. I think there just needs to be a blurb that a DM needs to tell the players what skills are going to be in his game and he can use his imagination or invent some if the common example skills listed in the book don't cover his campaign very well. But you are right, tailoring skills to the campaign is a big part of what I would advocate!
A DM could easily implement any of these skills into his or her campaign with the existing system if, say, cooking was important to the campaign's theme for some reason. Blackmailing someone seems implicit in Intimidation. Lockpicking and trap disabling are covered by a tool proficiency.
I agree with most of this. Cooking could be added if it was important. But we are talking about how 5e handles skills and that's basically as a static list that you pick from and cooking is not there at all (and I agree that it typically shouldn't be). I agree that blackmailing can typically be handled by intimidation but it's not always a perfect and in some campaigns it might be worth differentiating those skills. Yes, thieves tools allow both of those. I'd forgotten about that because it's not actually in the 5e skills section even though it's how I've always played.
Me "of all people?" What does that mean?
And I'm not resisting what you want to do, provided it's just for your own campaign. I think the current list is fine for the campaigns I run.
But this discussion isn't about my campaign. It's about how 5e does skills. What works what doesn't. If any tweaks would be good for the system. Is 5e fun and playable as is. Of course! But that doesn't mean there isn't room for improvement.
Listen, anytime you or anyone else comes back with something like, skill X is needed because it let's me do X things, or what you are advocating for is no skills at all, or 5e's skill list works fine as is then you are resisting even the thought of challenging the status quo.
Skills aren't made to allow anyone to do things. Skills aren't required to play the game as we both agree. Instead they are there to add some granularity and differentiation between characters. The problem with skills is that if they are implemented poorly then they actually take away freedom and interesting choices. They can become "trap options" where some are vastly superior and others are vastly inferior compared with each other. That doesn't mean we should throw skills out or that 5e did a bad job with them. But it does mean we should occasionly evaluate the state of skills in 5e and see if there is a better way going forward.
Who is arguing either of these points? Not me, certainly.
Question: Do players get to decide if they make an ability check in your games e.g. "I want to make a Performance check to impress the king..." or "I draw my sword and threaten his life - I got an 18 Intimidation check."
Others were arguing those points. You then jumped in with on their side and argued that what I said amounted to claiming that skills weren't needed (as a way to help them defeat my argument) which wasn't my point at all, nor was a skill less game something I would advocate for and neither was what I was saying something that could be used to advocate for a skill less game on its own. Now maybe I misconstrued your intentions, but you got plenty of likes for your comment there so whether intended or not that's how others took your post.
No players do not get checks by asking for them.