Monopolist Often Don't...
...Give up their monopolist positions voluntarily. They have to be compelled. And eventually, even slow moving outfits like the US government get their act together to do something substantive (the EU is like greased lightning in comparison...).
There are exceptions. IBM managed to avoid it, basically by being very keen to demonstrate how good a corporate citizen they were, back in the 1970s. IBM was then very different to the company we see today.
Google seems to have no such intention. What Google don't seem to realise is that there's a fine line to tread when operating a near monopoly, otherwise corporate breakup is inevitable. Instead they seem hell bent on antagonising regulators, and even the US politicians are beginning to make grumbling noises. They are not operating an effective long term strategy.
But then again Google's management has never been good at strategy, with their one track mind on how they operate. Their Android strategy has been woeful (China, updates?). Their services strategy has also underperformed (China again). It's going to take some imagination to survive intact, and I don't think they've got it. This is the price they're paying for their skewed corporate constitution, whereby wiser more experienced investors can inject management wisdom by influencing the board's composition. Instead the voting rights distribution amongst shares is guaranteeing that the management will drive the company off a cliff edge.
The UK's Digital Services tax could be the sort of thing that breaks the company too, if the idea spreads. It's easy for other countries to copy it, and 2% can be easily scaled up. And they cannot avoid it because it's based on taxing something that can be measured externally; the ads they display. And the tax man can always compel their customers to disclose how much money they've sent Google's way too. Basically playing an under-reporting game with such a tax could be criminally dangerous.
As things are I see nothing to suggest Google is going to be a consistent cash cow, like Microsoft are. MS out-earned Google by more than 3:1 last quarter. Google are going to fail, unless they face up to the fact that everyone will one day be fed up with them and will be prepared to break them up and tax them into the ground.