Apple changed a lot of things with the iPhone, but let's not get into revisionist history.
All the phones had some sort of way to get into quiet mode. Apple did it right, no-one else had.
There's a vast gulf between volume controls and a tactile feedback of 'is my iPhone on silent, [move thumb over toggle], yes it is, brilliant'.
And that was the genius of Apple. But not just there on all parts of the phone.
Just preordered my 4S to replace it. I admit I was a bit disappointed--I prefer the rounded back so I'd hoped for a case redesign. Even at this much of an upgrade [I don't have video, haven't been able to upgrade iOS in six months], I don't expect the "magic phone" feeling I had with the 3G. Far fewer people had smartphones at that time (May 09). Always startled me when my phone would create a stir. Now I get more of "wait, how old is your phone anyway?"
On the TouchPad that's like 5 seconds to change both.
(I understand I'm comparing a tablet to a phone but I never tried any other mobile OS so I have no idea how quick you can do that. I can guess it's like the TouchPad though.)
Post iPhone, you flick the hardware switch that you can reach while the phone is still in your pocket.