I would contend that is not the only reason. Plenty of times the bigger companies are just buying up their competitors. The most famous example being Instagram.

I would contend that is not the only reason. Plenty of times the bigger companies are just buying up their competitors. The most famous example being Instagram. Instagram could have been it's own big company, but now it's part of a monopoly. And that's just a big example which happened semi amicably. There are plenty of documented cases of VC funded companies throwing their weight around.