The $600 Flash authoring tool is the only way to produce Flash applications.
The free Mac OS X Developer tools (that require an $800+ Mac computer) are the only way to produce iPhone and iPad applications.
Both systems are as closed as each other.
Adobe claims Flash is open.
Apple makes no such claims. If you want to make iPhone or iPad apps you use Mac OS and Xcode, take it or leave it.
If you choose to leave it the alternative is HTML. A truly open platform for which authoring is as simple as editing text. There’s many HTML rendering engine implementations, the best few are totally open source with Apple being the major contributor to the best one, WebKit.
Adobe: not open, claim to be.
Apple: not open, don’t claim to be, contribute heavily to that which is truly open.