Thousands? Most that don't a) are games b) have goofy design.
You have to be very careful with redesigning native controls (see drop-down lists on the web), most of the time it's just an excuse for making the app not look "plain", instead of doing good design.
Thousands out of over half a million. It's very rare to see the default rounded rect button used anywhere anymore. It's even rare to see apple use it in their own apps.
You have to be very careful with redesigning native controls (see drop-down lists on the web), most of the time it's just an excuse for making the app not look "plain", instead of doing good design.