What does that mean? Technology changes, so the definition of a current smartphone (current models, not old models someone still have in their drawer or dresser top [where my original iPhone is]) will change with that technology. Not so hard to understand.
I was replying to someone who claimed that if it downloaded apps, and a couple of other things, made it a smartphone. In fact, that very thought about the original iPhone came to my mind when I read his claim. Personally I would say that the definition of smartphone evolves with the technology.
Depends on the processor. An 800mhz processor from several years ago is old. Not all current ARM processors run at 2+ ghz speeds. There are also current model processor made for various purposes that run at slower speeds. Things besides Android use ARM processors.