What's falling is the price of tablets. They're below $50 now on Amazon, with a 1-year warranty.[1] Low-end tablets are already starting to replace restaurant menus and TV remotes.
Phones are personal devices. Tablets are more place-oriented; they'll be in office conference rooms, hotel rooms, and restaurants for whomever needs to use them. They'll be too cheap to steal, and tied to a local WiFi key so they're useless elsewhere.
The main problem is keeping them charged. Phones have individual humans slaved to them to tend to their needs, but place-oriented tablets do not. The wireless charging industry needs to get their act together, unify their three competing standards (Qi, Powermat, and A4WP), and get a charging unit into every business hotel room and airline tray table, then start on conference room tables.