The DOJ lawsuit had nothing to do with Apple existing. The measly $250 million investment didn’t “save Apple”. Apple turned around and used $100 million of that to buy out PowerComputing’s Mac license.
Yes it did, but not in the way you're thinking.
Microsoft's investment into Apple and devotion to a dev team to port Office to Mac OS was what re-instilled developer confidence in the platform.
If you recall, Apple had $2 billion in cash and had just spent $500,000,000 on NeXT. The $250,000,000 investment helped ease the burden, but it was Microsoft standing behind the platform that really saved it. Same reason the "Year of the Linux Desktop" will be Year Never... developers don't develop for Linux Desktop because they have no faith in the platform one day becoming a huge market dominating offering that could share the spotlight with Windows and Mac OS.
And for the pedantic people out there, when I say "developers don't develop for Linux Desktop", I - obviously - mean developers of consequence. There is no Microsoft Office for Linux Desktop. There is no Adobe Creative Cloud Suite for Linux Desktop. I can keep going. The major players - the ones that matter - don't waste their time with it.
Microsoft Excel was first introduced for the Mac in 1987. Word was first introduced in 1986. PowerPoint was originally a Mac application that was acquired by MS.
In fact, MS always had a Mac team. Bill Gates was on stage with Jobs at the introduction of the first Mac.
I had Excel and Word back in 1992 on my Mac LCII. Of course it was pirated. They were like $300 a piece.
But MS had absolutely no leverage on the phone carriers. By the time the iPhone came out, Apple was riding high because of the iPod. Verizon didn’t accept Apple’s terms until they started losing customer to AT&T.
I'm not sure what leverage Microsoft would have had over AT&T or Verizon to block the iPhone.