Explain why governments don't allow companies to absorb as many smaller other companies as possible to kill off competition and to become more and more powerful?
There's many reasons, some obvious, others less so, but a lot should be common sense. One extreme is the company basically gains more power than the government itself.
Think of the game where everyone starts as small dots. The bigger dots move around and can eat any smaller dots and thus become bigger. Then they can eat any other smaller dots. Eventually, you are left with one huge dot that has absorbed everyone and e everything.
The end result?