If you draw trend lines and extend the very graph you posted from AMD's very own marketing slides done by their own projections, you'll see that ARM and x86 will find parity in growth and contraction. In fact, x86 has basically contracted as far as AMD thinks it will.
If you don't believe me, look at the growth rates of ARM between 2005, 2010, and 2015.
2005 - 2010: almost doubled
2010 - 2015: almost doubled again
2015 - 2018: flat, nothing growing
Look at the graph you posted again. If AMD agreed with you, ARM and x86 wouldn't be finding parity in growth while maintaining what AMD projects to be damn near equal market share.
ARM is going to stop growing so rapidly like you think. We've already reached the point with mobile devices where existing products are "fast enough" and people no longer need to spend $700 (with provider eating most of the cost) when they can do something and buy Moto E for $129 and get a good experience still.
As I've been saying, once this drop off hits, ARM will slow down massively. The only new market that remains for them is mobile and servers/HPC. I see them doing well in servers and HPC but you're over-exaggerating mobile laptop wins.
A quick search in the computer section for laptops @ amazon and sorting by popularity shows the most popular laptops to be:
1. Toshiba Satelite with Celeron
2. Chromebook
3. HP with AMD E2 APU
4. Chromebook
5. HP with AMD A4 APU
6. Apple iBook with G4
7. Dell with Pentium
8. Dell with Celeron
9. Acer with Celeron
10. Dell with Core 2 Duo
But my point is that you are doing the same thing the apple kids did when they were losing the market share war. They compare a few iOS models to a few Android models and then go "lol Apple is fine it still has more market share than Galaxy S2!" without realizing that iOS is already a minority (at that point) compared to every single Android phone.
My point is that even with two chrome books doing well on Amazon (and an iBook G4 and Core 2 Duo laptop are doing well too!), that's still a little drip into the ocean of x86 laptops, because Chromebooks are not as diverse so the sales are concentrated in a few models. So when you compare and say that Chromebook is doing just as well as some x86 models, you're forgetting that there's a handful of Chromebooks and there's an endless army of x86 CPU laptops.
EDIT: Juan, this is it:
https://translate.google.com/translate?hl=en&sl=zh-CN&tl=en&u=http%3A%2F%2Fnews.mydrivers.com%2F1%2F305%2F305092.htm
Lienhard: Last year we introduced a Piledriver (hammers) architecture, and achieved good market performance, there are about 30% growth, Kaveri also used Steamroller updates (excavator) architecture. FX Series of high-performance market positioning in the future will, within two years you will definitely see an update.
HEDT is coming back. Either jumbo APUs or dCPUs with dGPUs with HSA butter.