This is how it works in other games where you want to play multiple classes.
Make a character and pick a class => Level the class to max => Do content on said class => get gear
Make another character and a pick a different class => Level the class to max => Do content on said class => get gear
FFXIV's method:
Make a character a pick a class => level the class/job to max => Do content on said class => get gear
Pick a different class on same character => Level the class/job to max => do all content but the highest tier => gear up much slower due to caps/lockout
The main difference is that you aren't allowed to maximize your other classes in FFXIV unless you make an whole new character. Please explain to me how players that do this to gear multiple classes suck when they are putting in the work running the content. If anything, players that get Allagan pieces for their alt classes without bringing those alt classes to the content that drops it are more likely to be terrible at their alt class than someone that runs it on the class.
Your mentality also assumes that people can only be good at one job or like one job, which is far from the truth. It also undermines one of the pros of players being able to play multiple roles. Your healer friend wants to tank instead? That's fine, you can change to a WHM to let him tank. Someone is missing and you need to fill a different role? You can change to what's needed. However, with the current implementation of endgame, Your alt classes won't be as geared so naturally, your group will struggle a bit more. If you had just leveled a whole new character, your alt class would be just as geared.
