Antitrust law came about because near-monopolies had formed in the late 19th century.
Microsoft was almost a monopoly and tried to use that monopoly to shut out competitors in adjacent markets.
This is just speculation, but I suspect Microsoft's life-saving investment in Apple could only have happened after they had been targeted by antitrust law. Otherwise Bill would've told Steve to get lost.
I addressed some of this in detail in a more philosophical manner in response to a "sibling" comment of your comment, so I'll just be more specific here.
I believe that if it were not for various antitrust action (in both the EU and the US), MS would have continued bundling IE with Windows in a way that made the two inseparable. This would have led to the collapse of the Windows, because IE was too bug-ridden and security-vulnerable at the time, just barely acceptable. There had to be a separation of the two for Windows to remain viable. The EU had a particularly harsh ruling on this, IIRC.
Were it not for the EU, Linux, Solaris, BeOS, Amiga, or something else would have suddenly become much more important and would have taken up the slack. In other words, antitrust action may have "accidentally" saved Microsoft from their own mistakes.
I actually think this theory is plausible. (I know I actually was driven away from Windows because it was too virus-prone, and yes, this is for technical reasons, not just being the most used.)
Maybe MS and Windows would have survived just fine anyway. But the true moral of the story is, MS fundamentally cannot achieve a true monopoly in the operating system market, unless they get the government to ban all other operating systems. Unless other operatings systems become illegal, somebody else can always make a new one.
I believe that if it were not for various antitrust action (in both the EU and the US), MS would have continued bundling IE with Windows in a way that made the two inseparable.
"Would have continued"? MS still bundles IE with Windows and uses its backend rendering tech in the system. The decision made by the court was that they had to provide access to "secret" APIs, not that they had to stop bundling IE.
This would have led to the collapse of the Windows, because IE was too bug-ridden and security-vulnerable at the time, just barely acceptable. There had to be a separation of the two for Windows to remain viable. The EU had a particularly harsh ruling on this, IIRC.
But there was never any separation! All copies of Windows with the sole exception of Windows 7 in the EU come with IE as the default and only browser. The HTML rendering technologies are still the same (Trident). And IE is still the most used browser.
The decision made by the court was that they had to provide access to "secret" APIs
What did those APIs do? If they were APIs that one would need access to to make a competitive alternative to IE for Windows, then my story would be surprisingly accurate given the little that I remember. To be clear, the case I'm remembering greatly predated Windows 7.
Anyway, maybe I just got the story from some shitty pop news article many years ago and it's all wrong. But it stands as a hypothetical rhetorical device in the discussion about monopolies.
Microsoft was almost a monopoly and tried to use that monopoly to shut out competitors in adjacent markets.
This is just speculation, but I suspect Microsoft's life-saving investment in Apple could only have happened after they had been targeted by antitrust law. Otherwise Bill would've told Steve to get lost.
Would Apple still exist if not for antitrust law?