They were and made an AMD laptop last year,and the XBox is AMD powered.
But irrespective of this,the Surface Book 13 is overpriced. Its heavy and large. If Asus can engineer a laptop with twice the cores,and nearly double the GPU processing power,bigger screen and a huge 72WH battery into the same sized enclosure,it shows mediocre engineering on the part of Microsoft. I am not a Hipster,so couldn't give two hoots about what brand is on the laptop. Nobody is going to collapse at the size of your laptop branding if you walk into a Pret a Manger!
Intel and Microsoft is literally conning it's loyal customers by releasing stuff like this at this price. A 4C/8T CPU is under £150 in the current Intel range and these are not even proper ruggedised laptops. When Intel refresh its entire range next year,and moves off 14NM finally,then the people who bought these laptops,will feel regret. Intel like AMD will have lower power 8C CPUs,and the Surface Book 4 will probably be upto 8C.
This is one generation of laptops,I would feel confident in skipping if you really need an Intel CPU or that Microsoft/Razer branding. Intel is in a transition period with its lines,and people shouldn't get caught out when spending £1500 to £2000 on "light gaming laptops". £1500+ for a Intel Core i5-1035G7 is ridiculous pricing - I think I have seen laptops for £500 which have the same CPU.
I would compare it to people who got caught out buying P4 laptops before Intel released the first Pentium M based ones.