It took five years but finally every device in the currently sold iOS lineup have Retina displays. It also signals the end of the A5 chip but developers can’t get too excited to end support as iOS 9 will run on the original iPad mini. The fifth-generation iPod touch also includes an A5 … I think that will disappear soon. My guess is that it will be replaced — in contrast to the line just being killed — by a new non-cellular iPhone variant with a 4.7 inch display.
The Touch is a nice gateway drug into the iOS world so I don’t think Apple can drop the product entirely. The only way it could get completely axed, I believe, is if Apple can sell an iPhone at iPod touch price points. We aren’t there yet.