Ability scores and magical traditions

D&D has traditionally assigned spell-casters reliance on different ability scores, typically lining up with their power source. Intelligence measures reasoning and memory. Wizards cast from Intelligence. Wisdom measures perception and insight. Clerics, Druids, and Rangers cast from Wisdom. Charisma measures force of personality. Bards, Paladins, Sorcerers, and Warlocks cast from Charisma.

Why these ability scores in particular? I don't (entirely) care if the ability scores are highly questionable mechanics in and of themselves, I just care what the internal logic is behind them being assigned in this way. D&D itself provides no reasoning for the assignments, so I have to devise my own. My working rationale is that spell-casting ability determines how a caster casts their magic regardless of its power source: Intelligence indicates the study of magical theory, Charisma indicates forcing the magic to obey your will, and Wisdom indicates passively attuning to and channeling universal power like a Jedi knight. But these rationales don't seem to hold universally true in the class mechanics and fluff.

Wizards cast from Intelligence because wizardry studies and manipulates magic like a science. When you cast a spell, you are arranging the spell using your knowledge and understanding of magical theory. That makes perfect sense.

Paladins and sorcerers cast from Charisma because they shape magic through sheer force of personality. They don't understand magical theory like the wizard, they just brute force their way to the desired outcome. This makes sense, although it requires imagining Charisma as the spiritual equivalent of Strength and Dexterity, I guess?

Bards cast from Charisma because Charisma is used for the Performance skill. Since bards cast spells by performing magical music, it therefore follows that they would use the same ability score. This makes sense from a game mechanics perspective, but Charisma being used for Performance is questionable in reality. Just because someone can play an instrument doesn't mean they are a social butterfly. In fact, playing music is heavily linked to "verbal memory, spatial reasoning and literacy skills," so it makes just as much if not more sense for Performance (and by extension bard spells) to rely on Intelligence and/or Wisdom.

Wisdom is where I hit a brick wall. As it stands, Wisdom is a weird grab bag of perception, intuition, and bits stolen from Intelligence. For the life of me I cannot reason why Wisdom would determine the efficacy of divine spells, as opposed to a Jedi's Force powers. The caster is just channeling the power of their deity to cast the spell on the caster's behalf, so their own ability score should not matter. This would make sense if Wisdom was supposed to measure how "attuned" the caster is to their deity, like a Jedi is attuned to the Force, but the fluff for divine casters is diametrically opposed to that of Jedi. Jedi are vaguely pantheistic, whereas divine casters are generally henotheistic.

Warlocks are the second brick wall. The use of Charisma would suggest they brute force their way through magic like the paladin and sorcerer, but the fluff explains they rely on study of magic like wizards. The patron mechanic confuses things further by drawing a parallel with the divine casters. What exactly is the difference between a warlock patron and whatever empowers a cleric or druid? According to anecdotes, the Warlock cast from Intelligence during playtesting but players complained that it didn't cast from Charisma like it did in third edition. (A lot of the questionable class design decisions apparently resulted from players complaining that it didn't work like third edition, even when the proposed mechanics were clearly better balanced or more logical than third edition. Druid wild shape is another example.)

As it stands, I think the key flaw of the spell-casting ability mechanic (beyond the questionable definitions of the ability scores themselves) is that it shoehorns ability scores regardless of whether it makes sense from a fluff perspective. In addition, the mechanic forces every class to rely on a fixed spell-casting ability even if it would make sense to let players choose another to customize their character. For example: maybe there could be a divine wizard counterpart who studies divine lore and casts divine spells recorded in a prayer book (e.g. Heroes of Horror's archivist class), or a divine caster who casts from Charisma to indicate that they rely on divine power from within rather than attuning themselves to a deity (e.g. Pathfinder's oracle class).