I really, really want a physical keyboard.
I don't like the sliding keyboard either.
Droid 4 is a currently shipping phone that has one. I've been using it since Droid 2. Don't care for the extra heft and sub par picture quality, but love the keyboard when an emergency comes up and I have SSH into a server while away from a proper computer.
They're as outdated as rotary phones or cellphones with a physical number pad. Can you still buy them? Sure. Are there still those that desire them? Absolutely.
None of that makes them any less arcane.
You seem to have a problem distinguishing between "useful" and "trendy," based on your other comments in this thread. Mass-market popularity of a feature has no bearing one way or the other on its usefulness or "outdatedness".
I entirely disagree. They are both simply examples of what one is used to and therefore prefers. The only difference between a "valuable tool" and an arcane affectation is your personal preferences.
I have no problem distinguishing between useful and trendy. We're not talking about just mass market popularity, we're talking about these niche devices no longer existing. "Because it's trendy" isn't the reason that even companies that have no problem with spitting out endless models and variations have also abandoned hardware keyboards.
A full size phone headset, a rotary dial, a landline. All arcane affectations in the eyes of most, useful tools in the eyes of those that swear by them. In 10 years, we'll look back on hardware keyboards on phones the way we look at floppy disks. Most already do.