No more contrived than the reason why a regular sorcerer can't carry around a big basket of bat guano to cast fireball a zillion times. Spell slots have always come from the caster, not the components. Changing them to a deck of cards changes nothing about that.
I think I need to expand on this one. Maybe I didn't understand what you were claiming, but here's how I was looking at it:
The rules don't limit your spellcasting by availability of material components, but by spell slots. So a sorcerer simply carrying around a big basket of components isn't actually challenging that rule. He's gonna run out of spell slots long before he runs out of components. (And the DM should probably bring encumbrance rules into play as well.)
In my example of the Sorcerer with the deck of cards, he was narrating his spellcasting as being the result of throwing these cards, and that he had specific cards that different things. He was complying with the rules, but nothing in his fluff reflected those rules.
So a more apt analogy would be if your sorcerer with the basket of spell components also claimed that he could cast as many spells as he wanted, as long as he had the material components. Now, as long as he just talks about it and doesn't actually *do* it (that is, he never exceeds the spellcasting that would be permitted by the rules, however he narrates it) then I'd be fine with it. Just like I'm fine with the deck of cards sorcerer throwing cards instead of casting spells, as long as by doing so he doesn't exceed the spells per day defined by his class and level.
I see these cases as perfectly analogues to the 5 Int story: in both cases the player is re-writing the official description of something, but not actually changing anything mechanically.
According to what you and Max and Danny have written I would assume you would have a big problem with both of those examples, because once you allow the player to narrate it that way, what's to prevent him from actually demanding that he gets to cast more spells. Or, as I suggested before, what happens if he gets charmed by a Vampire who then orders him to keep casting until he's out of cards/components?
If I've got that wrong, and any of you would *not* object to a sorcerer as described above, then I'm genuinely quite curious why you see the two situations differently.