Transformers has alot of unique characters, all fighting a war. And there rarely ever been grunts or generics fighting the war (with some exceptions.) The Decepticons are known for grunts and vehicons, and their shown to have their own will and wants. They aren't empty husks. The Autobots are less frequently been depicted with grunts (either because most of the time their more Autobots than Decepticons or to give them something to fight.) But they do have them from time to time. My question is... Why are some characters generics? How does one become unique, and not all share the same body type? Are they born like that? Yes, there are many characters who share the same body type, but are unique by head or color. But the grunts are all depicted with the same body type, colors, etc. With the only thing shown to make them unique is the voice or size.
Marketability. In universe, I suppose the same way some people are just wage grunts and others are office superstars. Some cars are lemons that barely make it off the lot and others make it 20 years with minimal maintenance. In a greater sense, with a costly war, most of the identical soldiers could be from more mass produced lots. In the IDW comic, there's a conversation that at the beginning new Autobots somewhere along the lines that had to pass an exam and understand something like 14 concepts as a protoform. Then as the war went on, they dropped the exam and just had to understand 9 concepts. Then towards the end, 5 concepts. So you could reason that in certain universes, the "lines" start with everyone has their own twist(s) on their model that further customized over their lifetimes, then just some unique parts and head and a loadout predetermined from say, three choices. Then everyone is the same.
Well generics aren't always a bunch of clones sharing the same design. It's more rare but there are examples of some very unique looking generics. Beast Wars and Beast Machines reused parts from existing character models in order to make generic character models whenever they needed. The main reason people think Nightscream was a cassette prior to being reformatted is because his flash back contains what was suppose to be a generic robot who looks almost exactly like Soundwave. The UT also tended to reuse character designs from G1 as Generics even though we could identify what specific characters they based the animation models on in the context of the Unicron Trilogy they're totally different generic characters who just happen to look like G1 characters. In real world terms it's just a cheap way to save on animation to not make unique designs for characters who are only going to be on screen for a few seconds. In story, I'm not sure if there's ever been a canon explanation for why generics exist.
...if this was the asylum I'd just pat your hand and up your lithium dose rather than try to answer this...
Case in point: these generics from Transformers: Victory. All of them have unique designs. Picture taken from Transformers Wiki.
Generics are typically non sentient drones if they share a body type with each other, while unique bodied generics tend to be regular cybertronians who just don’t get any spotlight in the media in which they appear.
I feel like attrition is the simplest answer. TF characters referred to as “old,” like Alpha Trion, Kup and Megatron were once more common models. Over time, most of them broke down, emigrated or were killed in the war. Middle aged models like the seekers are more common. We actually see multiple bots with the same core model still alive, though their numbers are less now than they once were. They have modified themselves as they see fit over time like Starscream and Dirge having different wing designs. Now let’s say a new wave of bots were just built and entered service in the war. There would be many of them fighting amongst the older Cybertronian models. They aren’t drones or necessarily generics but fresh off the assembly line and in high concentrations. They haven’t had time to make any of the modifications you can see in Starscream vs Thrust. They may not have fully developed personalities or even names beyond their serial numbers yet. An example of a newly released model could be the Vehicons from TF Prime. Another way to explain this is like when a new toyline is released. When Siege came out last year, tetrajets were very common. Now, Earthrise seekers outnumber the tetra jets on toy shelves. The new seekers aren’t more generic than the tetrajets, it’s that the number of tetrajets has fallen over time due to attrition as people bought them.
easy answer. a) in media: Depends on the writer and if they want to introduce a new character. b) in toys: Hasbro got a new designer that did a new figure/mold that looks good and they want to have a new figure to sell and pull of the "new" thing for purchases.
I think the better question is at what point did cybertronians become unique? Comics aside, if we use the G1 cartoon origin Autobots were labor workers and Decepticons were the warriors/army. In an assembly line setting you have your Model-1 that performs task X, Model-2 does task Y and so on... So at a certain point the Quintesons stopped making various models. So where did the Orion Pax model come from? Where did the Megatron model come from? Are there more like them?
My headcanon is that the body types for land/sea/air grunts are like "uniforms" that a cybertronian would scan and assume once enlisted as an Autobot or Decepticon. Only when you're a certain rank or in a certain squadron/rank e.g. The Wreckers would you get the luxury of modifying yourself with a more unique form.