I agree that the sorcerer isn't iconic, but not because it wasn't in second edition.

Rather, the sorcerer isn't iconic (1) because fiction in general does not distinguish between sorcerers and wizards, so there aren't any major fictional characters that can be archetypically thought of as "sorcerer but really not wizard"; and (2) because it hasn't had a consistent role so far along D&D editions.

In 3.0, the sorcerer is the same as the wizard, only spontaneous. In 4.0, the sorcerer is a blaster wizard, except that regular wizards can also be blasters, and drawing its power from dragons, storms, chaos, or the cosmos (just like wizards, really). In 4.4, the sorcerer instead is an elementalist, except that wizards also have elemental spells, as well as a pyromancer specialty.

The bottom line is that WOTC has failed, so far, to create a meaningful and consistent difference between sorcerers and wizards. And this is why they're not iconic.