In that case it could still end up in a situation similar to weed, where it is legal according to states but not to the federal government. Especially for those states that legalized abortion access via constitutional amendment rather than a simple law.
I strongly disagree with this. In practice, supporting chrome does not imply supporting safari and vice versa. In particular, Safari is much, much slower about adopting new web technologies. Google basically implements support for anything they can think up, Apple waits for it become a ratified standard and then implements it only if they want to. Their JavaScript implementations are also completely different.