The problem is that Google isn't "too good" at selling online ads, they're just the most profitable because their monopoly makes it impossible for better competitors to beat them. That means the world is stuck with Google's mediocre/shitty service even though consumers/the market doesn't want it. Innovation stops happening, quality of life drops, the economy suffers, etc.
Apple's big lead in chips right now seems like a great thing, but if the government weren't so shit at regulating competition, we could've had breakthroughs like this a decade ago. Instead innovation is (predictably) moving at a glacial pace.
The free market only works when there is competition, so since our economy is based on the free market, it makes sense to write laws that protect it. Monopolies directly contradict with the basic operation of the free market, which is why they're bad.
It doesn't matter if it's a life or death situation. Things don't have to be dangerous to your health to be illegal.
