I use an iPad 5 as my sole computer, along with an iPhone SE. What a fantastic combination. I think the 2017 onwards description should be that: yes, a tablet can replace your laptop completely... UNLESS, you have specialist needs: e.g. 4K movie editing .. coding .. etc. 90% of people don't do those things and for them, any iPad offers a superior experience in screen quality, battery life, build quality, ease of use and all the rest.
If you look at iOS 11 and Apple's sales of iPad's since you'll see that they're far from discontinuing them. Tablets are the future. Not today's iPads yet, not the Surface Pro 4 (Thank god).. but they will continue to evolve slowly until every need can be solved with them and when the iPad does find a way for programmers or heavy-lifting movie editing apps.. it'll be far superior to what we know today as the desktop experience.
OP seems like he posted this to start a debate, well I've responded with my personal opinions on the matter.