"We have to make sure there are no monopolies" (or that monopolies don't "spread") is a dangerous approach, since it leads to the politician's fallacy. It may not even be possible to keep a relatively free market while making sure of that.
The question to ask is: are these EU investigations effective at reducing the number and spread of monopolies? And if they aren't, what should we do?
Because looking at the Microsoft case, the effectiveness seems dubious.
In the Microsoft case, the effectiveness was still noticeable.
The concept of the Microsoft case: Make sure that Microsoft can not get a monopoly in the web.
How it was done: Install no browser by default, let people pick. People chose what they had heard of, often Firefox or Chrome.
Result: It led to an almost instantaneous drop in IE market share on new windows installs.
And it most definitely helped end IE’s monopoly over the market.
With Google, it will be far more problematic, and might even end up with Google getting broken up into several companies, or even banned from some markets, or even forced to operate like a governmental monopoly, and integrate competing products equally as they integrate their own.
The question to ask is: are these EU investigations effective at reducing the number and spread of monopolies? And if they aren't, what should we do?
Because looking at the Microsoft case, the effectiveness seems dubious.