How do Apple get away with including iCloud in the OS without having companies like Dropbox up in arms? And they do call it "sync".
Microsoft used it's monopoly with Windows to edge out competitor browsers and practically killed Netscape's business. When you have a monopoly, there are special laws that apply only to you so you don't abuse the market.
I'm pointing out that it seems like MS is using its monopoly with Windows to edge out the Dropbox service.
Apple can be prosecuted under the same exact anti-trust laws as Microsoft, regardless of market-share, if they've managed to cause harm per the government's findings.
Using a quasi-monopoly to create another quasi-monopoly is not illegal. Owning a quasi-monopoly is also not illegal.
I find people are often extremely confused about anti-trust law and the actual laws (and relative lack thereof) related to monopolies.
Microsoft is not operating under a government consent decree any longer.
Microsoft using Windows to compete with Dropbox is not inherently illegal. It has absolutely nothing to do with market-share, it has to do with whether the government, on a case-by-case basis, decides that a company's actions caused harm, and it is purely a subjective decision.
Anti-trust law, I'll note, does not specifically or exclusively govern monopolies. The majority of anti-trust cases that have been brought forward by the government have nothing to do with monopolies.
It really isn't an apples to oranges comparison (no pun intended). It also comes up as a security reason, which it both is and isn't. You're skipping nuances of things here by equivocating a browser install in an os.