Hah! Sliding keyboard, that absolutely rocks!
Unfortunately HP played musical CEOs (three in less than a year) and one of them didn't see phones or PCs as businesses they should be in.
You're also stuck in either portrait or landscapr mode. Whereas a touchscreen smartphone can reuse the touchscreen for say watch a movie or use different input (like say gamepad).
I believe the current innovation trend lies in those small foldables. Of course, small form factor and dual screen has disadvantages for battery, repairability, and ridiculously high price.