Something kind of weird going on here. But honestly none of those are terribly good reasons barring maybe the 4th, and that can be solved in other ways. It won't happen, but again it's a problem that plagues the jobs from inception onward.
1. Those skip potions don't let you hit end game content without having done anything with the job.
2. Yes, you can run a job without a lot of experience. It's rather difficult to get to 80 without any experience as the job, though I suppose depending on how you view Pixie quests you could pull it off. This plan just makes it simpler, and again not really for any plus.
3. Given how many people I've ran into who clearly don't know what they're doing you're really only making me think we should probably dial back the boost potions, but honestly I understand the philosophy as it lets people play current stuff. But you're vastly overestimating how much people prepare before a dungeon or trial on average.
4. I'm more worried about the inverse, as a Scholar not knowing how to play right can easily wipe a party. DPS not knowing how to play will likely slow it to a crawl but usually doesn't lead to wiping. But it can happen, as I've ran into a Black Mage who clearly didn't know what he was doing, and it made all the fights drag. Coupled with poor plays from others it lead to wipes. It's also going to only increase if you're adding more characters who don't know what to do, to say nothing of raids.
5. That you did it fine is irrelevant. Everyone is not you. Everyone is not that Black Mage I ran with either mind you. But increasing the number of people with poor understanding of their jobs isn't a plus, and it only leads to more issues.
6. It really isn't a means to undo homogenization though. All the jobs aren't the same thing (that you think this really demonstrates you either have an abysmal understanding of jobs or a ridiculously low threshold), but again, having access to more jobs doesn't mean you can throw balance out the window. Which, again, is the focus. It isn't about "flavor of the month", it's about balance being the key deal.
7. If there are too many jobs then... don't play them all. You don't need to max level all of them to get a feel for them. If you want to then buckle in for a long ride. You shouldn't be trying a brand new job at level 80 anyways.
8. I'm likely older than you, and I certainly don't have the time to play this game as much as I want. This game is already very generous with free time as it is.
9. If you want to play as a Warrior I could very easily buy you a skip potion for it, would get you most of the way.
10. I practice tarot on a day to day basis, along with other methods of divination. I wouldn't remotely characterize it as introspective though. Perhaps you meant intuitive?
11. I mean, I wouldn't force a square peg through a round hole and pair it with any of them, that's kind of the thing.