The reason why I buy the greatsword for my wizard is because I want to use it
Again, knock yourself out. You have no fighting styles, you have a strength of 9, and you have to give up your spell attack for that round. If you have a 15 strength, you still have no fighting styles, but you have a pretty good melee at will. Using a sword never bothered Gandalf.
In a system where all it takes to be proficient at something is to buy the necessary tools and said tools are fairly cheap, the optimal choice (aka the choice everyone ends up taking once they realize the benefits) is to buy a set of tools for every task and either haul it around or keep it in a cart or something. To me, that breaks a great deal of immersion and it just feels absurd.
What? Carting stuff around because you need it to do stuff is called provisions, supplies and well... equipment. In other words, a baggage train. If you want to do a lot of stuff that requires specialized equipment... you SHOULD have a baggage train.
Carrying everything around you could possibly need in a backpack because you ignore equipment in exchange for skills, now that is immersion breaking.
If characters want to be skilled at a wide variety of things, then they can be if they work it into their character concept. But let's not say "you're skilled at a lot of things because you bought a lot of equipment".
Which is a sucker's game, because combat feats keep you alive and skill feats don't.
because if this line of reasoning is applied to all skills, skills lose meaning in my mind. I'm a locksmith because I have a set of picks? Am I a scholar because I own a few books? Am I an expert warrior because I have a sword?
Yes, and yes. No, because you have no strength score and you haven't spent your class abilities or feats on combat stuff. Also your strength or dexterity sucks, which is why you became a wizard.
I don't see any kind of issue with this scenario except that the ranger should probably be less proficient at the task than the rogue, since the rogue has had a ton more practice and real-world experience.
He practiced when I wasn't looking, in the party downtime while they healed up or spent their money from the last adventure.
I think I'd disagree that everyone passing tons of skill checks will not break the game, as skill checks might be a dominant part of any given session depending on the circumstances.
It just means they will succeed at their mundane goals. But everyone failing skill checks breaks the game even more, and it breaks it all the time. Nobody bothers to sneak in low level new-school D&D games. Doesn't that bother you? Here they are, bottom of the food chain, but because only one guy can make stealth checks they crash through everything anyway. Doesn't it bother you that fighters have to choose between being good at fighters and being good at everything else?
One can imagine that the ability to craft items based solely on owning the tools required to do so could create long-term problems.
If you can imagine it, then you can give me examples.
I have my own solutions to the party wanting to do things as a group. I see no reason to ask for ride checks every 5 seconds just because the party wants to ride on some horses. I also don't see why people who want to be involved in intrigue at court can't simply do so. they may not be as successful as the person who has been investing their character concept into such a task, but I do not overly penalize them.
So you just handwave skills away entirely and give them the chance to succeed. Okay, but that's not more immersive than simply saying that people know how to do what they want to do. In fact, that's exactly the same thing.
Well, I never "kicked" anything "out of the game" since it was never in the game to begin with. Your idea is a proposal to solve a particular problem. In my eyes it is not the "optimal" solution. Here's my approach if someone wants to do something like pick a lock: do you know how to do that, and if you do, why? If they can provide a reasonable explanation, then they can go ahead and try and we'll let their stats and such determine the outcome. I follow a similar line of reasoning with almost any attempt at anything.
Then why are you fightin with me? You've just conceeded everything, because that's exactly the system I'm describing. Someone has a reasonable explanation of why they can pick locks, they buy lockpicks, and they pick the lock. Someone has a reasonable explanation for owning a blacksmith shop, they buy a blacksmith shop, and they make items from iron.