i doubt the game makers gave it that much thought. bacteria have NO (zero) intelligence. people often mistake for intelligence is actually a set series of genetically programmed reactions. for example, bacteria know to go dormant when cold weather comes. for someone who didnt know this, theyd see the bacteria going away as the weather got colder and come back as it got warmer. to them, it would seem like the bacteria chose to leave and then come back when in fact it is designed to do this on its own with no thought. bacteria do not react to one another. as far as bacteria is concerned, it is on its own completely. human cells stop dividing when they are touching other cells on all sides, but bacteria (especially engineered ones) do not do this. they eat and divide. thats all. they dont choose when to do so. they do not swarm. the reasons they thrive in one area or another is merely due to environmental variables. as i said earlier, not all crust is the same and the blight could be following less dense minerals in the ground, following veins of salts or it may have a preference to higher temps. keep in mind tho, preference doesnt indicate necessity. even though we might not like water, we can still swim and survive there. we might not like the snow but we still live in it. the blight might not prefer the surface, but they still multiply, but perhaps not as fast. I have the belief that the blight is following some sort of underground aquifer which may or may not be dried up (we can debate what makes up the aquifer later) or is following lava tubes or veins of minerals which it has a particular taste for. I think these things can account for the novellas observation that blight extends beyond its outermost boundary underground. the only creatures with swarm intelligence are higher animals like fish, insects and birds. bacteria cannot have this. the tendancy of bacteria to form into colonies is also not an aspect of intelligence. the organisms simply identify a food source and do not move on because no more is present. if the food runs out, they will remain in the last place food was and will remain in a colony either until they all die or a nearby food source is found (by nearby i mean nearly touching the colony).
one of the most common experiments i did was to culture bacteria. one time we arranged puzzles and even gladiatorial fights between colonies and although sometimes you want to think there is a rudimentary intelligence there, a simple set of genetic commands can do some amazing things without being intelligent. one of my favorites is when myself and the other lab mates cultured our best colonies over about a month. at the end, we took our best cultures and did a plate smear consisting of one persons culture on one side, another persons on the other with a line in between them drawn in sharpie on the underside of the plate. we put them into the incubator and took pictures of them every day. it was interesting to watch them "fight." once the colonies grew enough, they would attack eachother. their method was to grow a long tendril or vein going out of the colony and into the other. all bacteria produce toxins and when under attack, they begin to produce antibacterial toxins. the bacteria in the vein nearest the opposing colony would begin producing toxins to kill the enemy colony. one of the plates showed a vein attacking the other colony, but it had made a vein going around the vein attacking it essentially making a "left hook" sneak attack. while all of us were very impressed (myself most of all), all of this is nothing more than a series of reactions. it does not mean the bacteria decided to retaliate to an attacker to survive. When the bacteria detected substances that it and those of its type werent producing, a gene was triggered telling them to produce toxins. the bacteria were never aware they were under attack. the profile of the toxins they produce simply changed slightly. all they know how to do is eat and divide.
also, i dont remember reading about any blight-infected computers. the blight is supposed to destroy anything even mildly organic and savant computers are not just optronic in construction. In the game, ALL buildings and units go offline. This should apply to savant computers as well.
