In my opinion, its based on the perception of the companies combined with the impact they have on the general consumer market. Eg 70% of phones run Android, only 27% run iOS which makes Google a much better target to go after.
Same situation with personal computing, Windows was like 80% of the consumer/business market when the whole browser thing took place. MacOS was something like 5%. Also I've never really heard of someone complain about Safari compared to IE/Edge so maybe there wasn't any traction for something like that
Maybe someone has a better/more accurate answer than that but thats just how I've been perceiving it.
Same situation with personal computing, Windows was like 80% of the consumer/business market when the whole browser thing took place. MacOS was something like 5%. Also I've never really heard of someone complain about Safari compared to IE/Edge so maybe there wasn't any traction for something like that
Maybe someone has a better/more accurate answer than that but thats just how I've been perceiving it.