the fact that Apple forces all apps to be purchased through their own app store just as well be seen as anti-competitive?
No, not according to the more pro-active EU competition/monopoly laws or similar US laws. Apple's market share is too small to fall under "monopoly" in any or all European countries, where the distribution is quite varied from nation to nation. Scandinavia is not at all representative of the European handset market as a whole, my dear neighbor.
Furthermore the fact that a product only supports its manufacturer's services is not a violation of any doctrine here or there. The cases involving Microsoft has confused the general public, it's not illegal to only provide your own service/software/accessories. It's when that affects the general market to such a degree that it become detrimental to competition in general. US laws treats and views this differently than the EU does.
In the EU a monopoly is by its very definition seen as detrimental to consumers and must be acted upon. Until Apple constitutes a monopoly or is the dominant force it's not realistic to imagine any action by the US or EU. Apple's great influence does not constitute market power. At the moment Google's Android has the clear majority of consumers in their hand, or rather vice versa.
If the EU force Apple to have a browser ballot on iOS, I do believe Steve Jobs will be turning ever so violently in his grave
What? The man who forced Microsoft to settle [the lawsuit Apple brought against them] in return for buying Apple shares, making Office for Mac and bringing Internet Explorer to Mac OS!
No, I'm sorry, Safari is just a "pet project", Apple needed it to for their O/S to stay valid - and avoid Microsoft's grip. The very reason Microsoft was forced to open up by the EU was because their own browser skewed and hindered the market from developing. WebKit is an open source project, as Google and now even Opera proves. Apple doesn't have any greater advantage than say Google Chrome on Mac OS X. What possible arguments do you have?