I don't mean to annoy you, but your whole understanding is wrong. It's kinda funny to say it that way, but it's true.
The driver is only one part of why an earphone sounds the way it does. Taking the driver out of the context of the cable and/or acoustic filters and/or electronic filters, housing/shell materials, etc doesn't give you anything--it certainly doesn't give you the bass/mids/treble/whatever from a given earphone. You can't just glue it together with another driver which has the bass/mids/treble/whatever from some other headphone and somehow get anything that magically sounds like both. The tuning process is not nearly as easy as you are describing.
An example: One well known earphone company went and changed the materials that held the transducers in place (a more complex version of the "glue", if you will). This changed the sound enough that the iem was considered to be a new generation and rightfully so, as it had tuned the sound differently in several ways.
Just as the correct answer to someone who says "well, why can't we just add some gorilla dna to humans and then we'd be super strong?" is "that's not the way it works, there's a lot about genetics you'd need to know before you would have the background to understand why it's not that simple", here the only real answer is "that's not the way it works..."
