There are many reasons for the microbes not just surviving on this planet for four billion years but also dominating it.
For instance, they tolerate individual microbes that many of us would consider 'defective' and 'life unworthy of life' if they were human.
They don't try to remove them via eugenic programs (sorry can't use that term today, I meant of course via genetic programs.)
In fact, in times of existential crisis, they produce way more of these freaks and misfits, hoping against hope that they come up with a new way to survive.
Resting assured that it will be freely and quickly passed from one microbe to another around the world via HGT.
"With help from all, there is hope for all" and the microbes survive their latest crisis to live to see another billion years.
But we primitive 21st century humans are limited to just some of the genome of Mom and Dad --- we live in the closely guarded genetics of exclusion.
Genes treated as if private intellectual property.
You know : near-century long copyright lengths, patent wars, billion dollar brand names, hotly defended trade marks, closely licensed logos.
Microbes, by contrast, have a sort of free library card at the global lending library of usually useless but now really useful genes, via a process where genetic material from one individual is dumped in the common living area for all to take up and pass on, freely.
Its called HGT (horizontal gene transfer) and it is the genetics of inclusion.
A human equivalent ?
Public Domain, copyleft, open access, open data, open source.
So, for an example, thanks to Dr Martin Henry Dawson and Pfizer's John l Smith, penicillin was and remains Public Domain : anyone can make it and anyone can buy it and use it to save lives.
Ten billion of us since 1940 better off thanks to a sort of herd immunity this gave us from once endemic fatal infections.
Some microbes and fungi originally spread the ability to make penicillin via HGT.
And even more still spread the ability to resist penicillin, also via HGT.
C'est la vie ...