But this does not make iOS "closed". You can get whatever widgets you want built using web technologies, and they run like apps.
And if you're a developer, you can put whatever programs you want on your device.
Since all the open advocates should be advocating open source as well, why complain about iOS? IF you want to put open source software on your device, you can just compile it. Apple gives you the development tools for free (the core of which is itself open source) and charges $99 for handling the certificates an authentication for apps.
But you can put any app you want on your iPhone if you're a developer.
IF you're a consumer, you're not capable of compiling apps for your android phone either anyway.
(For some values of "developer" here I'm including enthusiasts who may not really be able to program but are find with compiling code.)