I think part of the difference was that M$ was intentionally putting up roadblocks on their platform with no other purpose than to block potential competition (e.g. Netscape vs IE). Apple will be guilty of the same thing if they in turn start using the AppStore guidelines of 'no duplicate OS functionality' to boot all of these players off of the platform rather than letting them continue to compete and differentiate their offers from Apple's.

I remember reading yesterday that some camera app was forced to remove the use volume buttons as photo taker or so.

There was several examples of apps that essentially 'went out of business' like Konfabulator, some early theming engine for Mac and the like with some dubious practices from Apple.