As an app dev, I bought the iPT because it was pretty much an iPhone without the phone.
I don't need or want the phone (or the data plan payments). The iPT was perfect for this.
The rMini hit a real sweet spot, you can carry it around and yet still fit it into a larger pocket or inside a clipboard, perfect for people on the move.
If you look back, the iPhone/iPT were very close to the same.
People can use WiFi to make calls and major parks and many businesses offer free wifi.
Many people don't make calls, they text or post on social media.
Phone calls are 1on1, text/posts/snaps are 1toMany.
Point:
They are locking in their customers.
This is the same BS the ink jet printers companies do... they sell you a printer and the cartridges are all different, they charge out the nose for dirt cheap ink and fatten up their wallets.
We The People

don't mind fattening up someone wallet, we just wanna get something good out of the deal.
Just heard Nexus isn't making the 7 anymore. Maybe it's time to look at Microsoft, they have multi-tasking 8" tablets from other manufactures that will run Android or Window (your choice).
Apple doesn't seem to remember they were a few short months from bankruptcy... All the money came from the customers... We have a choice, they just made the choice a bit easier.