In fact, I think it's an Android trend that has migrated to iOS. It works better on Android, IMO, with its hardware menu button.
The only phone I can think of that doesn't have that is the Nexus.
Interestingly, the button that HAS died is the search button. Any device I've seen with a physical home button has opted for a long press to be the app switch, and then to leave the menu button in.
Personally, I like the menu button. It feels very natural on my SGSIII (and also did on my SGSI and Galaxy Tab). It feels weird to hunt for the soft menu button (either top or bottom) on my Nexus 7.