Ok, but the ants communicate so that something can be achieved. What do the microbes achieve en masse?
They have massively influenced all life on earth.
In multiple ways.
Just one example. Look at the Black Death.
Probably gradually led to European democracy.
How? Killed a third of the population of the UK and Europe.
Massive dearth of peasants. Peasant labour became scarcer and hence more valuable...peasants began to revolt and generally act up. They got killed a lot for their pains, but it is arguable that the Black Death was of enormous importance in gradually leading to the end of feudalism.
There are lots of books on the subject...eg: