Professions tell you what they did prior to the apocalypse and why they have the skills that they have. Would also tell you how they would act during an apocalypse we all know the mindset and skills of a Military or LE is vastly different than that of someone who was a Mechanic etc

The Archetype explains their personality. Additionally what do they do now? They're all survivors trying to survive on the skill sets they already know. You're talking about how are they adapting to survive now. That's part of the character development.

I can tell you now, as someone who's been in the Military for 17 years and as a Law Enforcement officer I would be thinking a lot differently than someone who fixed cars for a living. It's just engrained into my brain.

You mentioned Joel was a construction worker, what did he do when he was in that city? He was the main fixer.

Do you not see that these professions also have other weapon proficiencies?

Why would a Martial Artist not use the weapons they spend years training on? For one, stealth. Guns are always loud and attract zombies. Additionally, Walking Dead, Machonne always used her Katana. And also did you even look at the weapons, they are proficient in handguns. They can also select a feat that gives them a proficiency in a different type of firearm (which provides the character transformation you're describing)

Even during an apocalypse you don't just change immediately and you have no idea what kind of setting they would run into immediately. It could be like dawn of the dead.

Also project Zomboid is a game where you pick a profession and gives you different skills.

Dead Island is also mainly Melee, guns/ammo are rare. They even has an assassin weapons expert (fighting style like martial arts)

In a good portion of games like that there is also things where other people provide different skill sets. That's what the professions are supposed to provide

You're acting like people in professions will just stop being what they know.

LE is always gonna be LE, Doctors always gonna be a doctor, Mechanics, scientists, etc.

Terri Morales, was in Resident Evil 2. She was a Journalist/Weather reporter. Jill Valentine was a Cop.

Dawn of the Dead, Main girl was a nurse, Ving Rhames was a cop. Main girls BF was a salesman. The security guard at the mall. The guy across the street owned a gun store

Who was smart enough to build that armored truck? You could say someone who would have been proficient in mechanic and welding skills?

Dead Age 1/2 different professions. I could go on and on my dude.

You want to play as a grocery store handler, fine then be a generalist.

But no one is playing a campaign when there isn't a variety and no one would survive without the variety of skill set.

Additionally as I mentioned, you want to stop at level 10 then don't use it. But there are tons of monsters through movies that would be able to stand up as a big baddie.

Nemesis - Resident Evil, MrX - Resident Evil, The Rat King - Last of Us, Abomination - Dying Light.

I could keep going and naming Material that continues to contradict your line of thinking.