Brands that define an entire product industry.

What kind of advantage is held by branded products that become the representative brand that all products in that industry are associated with? I began to think about this as I was watching people order drinks at a wedding. I thought about how people would order a rum & Coke, or 7 & 7 (for you non-drinking folks that would be Seagram’s 7 whiskey and 7-Up) rather than use the generic terms, rum & cola or whiskey and lemon-lime soda, although to be fair on the last one it’s a lot easier to just say 7 & 7. At this particular event I noticed that several of the alcohol brands used were not those requested by name, basically because there was only a limited alcohol selection. There was no Seagram’s 7, and another Canadian whiskey was being substituted without question. But it goes beyond the alcohol, I didn’t ask about the brands of soda but the bartenders could easily have been substituting Pepsi instead of Coke or Sprite rather than 7-Up.
Based on this initial thought I made a mental leap and began to think about products that are identified by a brand name rather than generic description. A perfect example is Kleenex, because no one I know says they need to buy facial tissues, they go to buy Kleenex. Not that there aren’t some reasonably well known competitors, Puffs for instance. But what kind of advantage do products like Kleenex, Band-Aid, or Q-Tip derive from being the brand that is in effect the industry standard? While I haven’t done any deeper research on this (yet) it would seem to me that these representative brands have a significant advantage over the competition based on name alone.
Obviously there are those consumers who could care less about brand names and go with whatever is cheapest or with another brand they prefer more. But regardless of that, I bet they still use the representative brand when referring to the product in general. Rum & Pepsi… it just doesn’t sound the same.