Yes it is...
my thoughts are it will happen in Leopard.
http://roughlydrafted.com/RD/TechQ30...X_Leopard.html
As for the iPhone locking...
I think that was driven by AT&T.
Cell phone companies are as bad a credit card companies.
AT&T got all crazy and demanded Apple lock the phone up.
My hope is Leopard will allow third party installation through iTunes.
Maybe even purchasing through iTunes after the application has gone through a review process.
Or installation of 3rd party apps will be installed though iTunes but not necessarily via the store.