It certainly won't happen until they figure out how to get rid of the huge plastic cutout for LTE antennas, I would think. Marketing is strictly Wi-Fi models now. And nobody is saying LTE will never be cheap enough to just build in, just that it is not adding $130 value for a lot of people, and that number who won't need it just grew with Instant Hotspot. You don't pull out your phone. You can connect as easy as when you find an open Wi-Fi network (unless y'all are savages who never use your Wi-Fi). No passwords, no pulling out your phone.
It really just is so easy now and Wi-Fi is in many places you'd be with something as large as an iPad as a consumer.
But I (and many others) won't use public wifi unless I'm just surfing. I certainly wouldn't use it for banking etc. And like I said, I travel a lot so I can't just wait until I get home to do some things.
It may be easier, but it still is not AS easy as just having a cell tablet. And with the advent of being able to use shared data it has become easier and less expensive.
Everyone has their own opinions. What works for me might not work for you. But I suspect there are enough people like me to convince Apple et al not to drop cellular options.
So, no, if Apple ever stops offering cellular tablets I simply won't buy one. Someone else will certainly meet my needs and wants.