Because other regions support ony CDMA bands and exynos didn't not supported CDMA bands that's why. And in India they didn't use because their Exynos support GSM and India runs on GSM and they were also do some cost cutting so that they may earn somr profits. Please mark as solution by clicking on 3 dots on my comment.
I have no personal issues with Exynos as long as it's having same performance and efficiency. But their 990 was just bad and they should've used SD865 instead of it. Exynos 1000 as per the leaks is gonna be very good and its coming with AMD GPUs, no more Mali craps but yeah lets see what they does