The key app is the browser
"Where would Mac be without Office, Adobe, and a few other key apps?" you ask? Well, I happen to own two Macs and have none of these "key apps".
Maybe that Apple would be exactly where all those iPhone / iPad / Android / and Internet users are?
*The* key app on my Macs is the browser. My document editing suite is Google Apps: I can edit and share my documents and spreadsheets between Windows, OS X and Linux as long as I've got a browser.
To keep on with your example, should Apple and Google have decided that old MS-DOS application from 1993 had been crucial we'd never have got the iPhone / iPad / Android devices.
I, for one, much prefer Apple's approach than MS's approach.
If Adobe doesn't like the userbase that Apple is providing them, they can focus on Windows-only but don't get mistaken: there are a *lot* of app developers willing to fill the Photoshop gap.