Another AMD's fanboyism, LUL. Using Surface's Laptop as a evidence of AMD's OEM indicates your biases, not opinion.
The main reason why Microsoft uses AMD's CPUs and GPUs in Surface Laptop is that, the Surface Laptop is too expensive to sell well. There is no person who want to spend $1400 to buy a Ultrabook, which is not 2-in-1 and not supporting long battery-time. What's more, without 2-in-1 or convertible, touch screen becomes non-sense. That why Laptop sell much worse than Surface Pro and Surface Book.
However, the Vega 10 need 30W power to catch up with 1065G7's Iris Plus graphics, which only need 12W. The R7 H-series also needs more power than Whiskylake.
And in this price of about $1400, there are many substitutes, such as ThinkPad X1 Carbon, ThinkPad X1 Extreme, Dell XPS-13, HP Spectre and so on. None of these failed to provide a better price-quality ratio, a more perfect screen, and longer battery time.
Why OEM's choose Intel as first choice? The foremost is that Intel provides a better price-quality ratio, more stable platform, and higher game-performance. You should keep in mind that i5-9400F's game performance is equal to R5 3600's, i7 8700K's is equal to R9 3900X's, according to Computer Base, TPU, tomsHardware and Techspot. And you will see that the price of i5-9400F is so low that it becomes best choice for general gamers. The i7-9700KF also in the same situation, which plays better than ALL Ryzen 3 CPUs.
You don't need to doubt that more than 90 percentage of high-end CPU home users is just for gaming. The gaming performance values most.
Why the game performance is worse though AMD's 3900X has more cores? That is latency. The CCX architecture's inherent problem is latency is more higher that intel's Ring-bus architecture. And the CCX, Mesh and Ring-bus have its advantages and disadvantages, but I think that's not important for you because you won't be faced with the facts or you are not a senior menber of Hardware and lack relevant knowledge.