IIRC MS tried to add the big Google apps on WP, especially YouTube. I only remember for YouTube's case but google stepped in to block MS's efforts every time they fixed something broken. Clearly fair competition.
Of course it doesn't excuse no other apps that were mainstream are on there (or were but not supported for very long as MS stopped paying for them tp be on their platform IIRC).
I do think by WP 10 they lost the plot. WP8 was peak but alas that time the market was going all app ecosystem.




