#The Borg are information addicts

The Borg is a cybernetic hive mind/superorganism whose sole purpose is the pursuit of perfection. It does this through assimilation (in particular, of knowledge, technology and biology).

So when a species or population is assimilated, they are injected with self-replicating nanoprobes that infect the host organism. Upon infection, one of the immediate functions of Borg nanoprobes is the construction of a neural transceiver which links the host individual up to the hive mind—a virtual network of the minds of all Borg drones connected via subspace (sort of like a distributed computing cluster), resulting in a single collective consciousness.

The more species and populations are added to the collective, the more advanced/intelligent/powerful the Borg become. Although drones are robbed of their individuality, their creativity, their personality, etc., the experiences and knowledge of each drone feed the Borg's ability to improve itself, to adapt to threats and to strategize.

This is how and why the Borg assimilate. So it wouldn't make much sense for the Borg to just toss out the valuable knowledge and experiences of their drones — which is arguably a far greater prize than the physical technology they capture.

The Borg isn't interested in wanton destruction and much prefer efficiency over waste, so you'd expect them to save and catalog every bit of information they come across.

#The Borg cluster has plenty of storage

As to how it's possible for the Borg to retain the knowledge of every individual they assimilate using the brains of every individual they assimilate? Well, just because you obtain a billion hard drives and shuffle the data around between all the hard drives and re-organize the data, doesn't mean the volume of the data has changed. Remember, the Borg don't really synthesize original knowledge on their own. They are almost slavishly dependent on assimilation for acquiring new knowledge and only recombine or make incremental improvements on assimilated research/technology (e.g. the Omega particle).

And that's before you even take into account the cybernetic enhancements that Borg drones receive, which allows Seven of Nine to become possibly the most advanced/intelligent (or at the very least the most knowledgeable) human alive in the 24rd century (with the exception of One and Reginald Barclay while he was under the influence of Cytherian control).

The Borg are information addicts

The Borg is a cybernetic hive mind/superorganism whose sole purpose is the pursuit of perfection. It does this through assimilation (in particular, of knowledge, technology and biology).

So when a species or population is assimilated, they are injected with self-replicating nanoprobes that infect the host organism. Upon infection, one of the immediate functions of Borg nanoprobes is the construction of a neural transceiver which links the host individual up to the hive mind—a virtual network of the minds of all Borg drones connected via subspace (sort of like a distributed computing cluster), resulting in a single collective consciousness.

The more species and populations are added to the collective, the more advanced/intelligent/powerful the Borg become. Although drones are robbed of their individuality, their creativity, their personality, etc., the experiences and knowledge of each drone feed the Borg's ability to improve itself, to adapt to threats and to strategize.

This is how and why the Borg assimilate. So it wouldn't make much sense for the Borg to just toss out the valuable knowledge and experiences of their drones — which is arguably a far greater prize than the physical technology they capture.

The Borg isn't interested in wanton destruction and much prefer efficiency over waste, so you'd expect them to save and catalog every bit of information they come across.

The Borg cluster has plenty of storage

As to how it's possible for the Borg to retain the knowledge of every individual they assimilate using the brains of every individual they assimilate? Well, just because you obtain a billion hard drives and shuffle the data around between all the hard drives and re-organize the data, doesn't mean the volume of the data has changed. Remember, the Borg don't really synthesize original knowledge on their own. They are almost slavishly dependent on assimilation for acquiring new knowledge and only recombine or make incremental improvements on assimilated research/technology (e.g. the Omega particle).

And that's before you even take into account the cybernetic enhancements that Borg drones receive, which allows Seven of Nine to become possibly the most advanced/intelligent (or at the very least the most knowledgeable) human alive in the 24rd century (with the exception of One and Reginald Barclay while he was under the influence of Cytherian control).