True. Modern corps have learnt the lesson of disruption.
I guess the only way it could happen is if it didn't look like a threat until far too late, such as totally different customers (e.g. third world), doing something completely different and no where near as good (e.g. markdown a threat to Word; iOS/android vs Windows)
Two of those 3 are peripheral to the tech world. They employ tech to disrupt other industries. And dropbox is not disruptive. It competes with similar offerings from the tech giants.
But stuff like Oculus is bought in its infancy - that is not desire to profit, but to control. FB could have acquired 20-30% of the company to provide them with liquidity.
I guess the only way it could happen is if it didn't look like a threat until far too late, such as totally different customers (e.g. third world), doing something completely different and no where near as good (e.g. markdown a threat to Word; iOS/android vs Windows)