I'd put a fourth point, the APIs they give to third party products are inferior to what they give to their own, always. So even if you wanted to, you could not

I'd put a fourth point, the APIs they give to third party products are inferior to what they give to their own, always. So even if you wanted to, you could not match the experience of being all-in on their ecosystem. That's intended, so that other products do not compete with theirs and look inferior.