Anyone who buys apps would have standing, imo. but the developers/dev tool makers might have a better chance. Hell, if you go even farther, you could say other smartphone makers have standing - but they'd have to make a different kind of challenge.
This is a chicken-egg situation. Apple has Apps, so more people buy iPhones than other phones. with Adobe's dev tools, devs could make apps for more than one platform - that is a threat to apple. When apple shuts this down it is an anticompetitive act against other phone makers. Because if devs could put apps on more than one platform, then other platforms would become more appealing.
This is a chicken-egg situation. Apple has Apps, so more people buy iPhones than other phones. with Adobe's dev tools, devs could make apps for more than one platform - that is a threat to apple. When apple shuts this down it is an anticompetitive act against other phone makers. Because if devs could put apps on more than one platform, then other platforms would become more appealing.