I don't think that the 2017 iPad "ensures" any of that.
Apple released the iPhone SE and it didn't impede sales on the iPhone 7. Look at the flack people are giving the 2017 iPad. Sure, people here are not necessarily typical consumers but they INTERACT with typical consumers. And they're telling them that the 2017 iPad is "old" technology and to "go Pro".
I'm a big fan of the 2017 iPad, but if you can't see that there are significant differences between the iPad SE and Pro (worthy of the price difference) then I don't know what to say.
The market for mobile phones is very different then tablets. Mobile phone are an essential everyday item whereas tablets aren't. Apple just released a brand new iPad for significantly less money. Is it worth spending $300+ for a slightly better screen and processor? I honestly don't know...