Forza motorsport vehicles migration to Horizon

I ve been trying FM7 lately and found out it has some amazing vehicles like the Alfa Romeo GTV, which was an amazing car design and performance wise.

Why they dont bring em to the Horizon platform? it should not be that difficult, after all it is all modeled and ready to go. And there are many other gems that we dont get.

I get the impression that Playground Games, and Turn 10 Studios do not work together as team members, but only share their origin with Forza Horizon 1, and 2.