Sorcerers are "spontaneous" spell casters. They don't "learn spells" the way a wizard does; their spells aren't granted by a powerful extraplanar entity the way a cleric's, paladin's, or warlock's are, they aren't drawn from nature like a druid's or ranger's. They have the same names, because they have the same effects -- but they come from innate magic within the sorcerer's being; a sorcerer becomes a sorcerer because of his magic. He can, with some experience, bend the spells, changing fundamentals of how they work (multiple targets, touch spells at a distance, and so forth), or rearrange spell slots.
Why, then, should sorcerers have to use material components to cast spells?
Bottom line -- is there reasoning given (beyond the small amount of material in the PHB) on why sorcerers have to use material components like "prepared spell" casters such as wizards, or divine casters like clerics? If you draw fire from your essence, why would you need a ball of bat guano?
Note that I am not looking for game design reasons (such as balance or anything about designer intent) to explain this, only in-universe explanations for why. Please support all answers with the appropriate evidence and support from lore and avoid conjecture.