I can't speak for the others, but the Samsung Galaxy Store does come pre-installed. However, Google paid Samsung for the Play Store to be the default action for app installs. So you get both stores and can pick which one you want.
That's just two options from two big players who cooperate, and only on some devices.
The Samsung galaxy store comes pre-installed on Samsung phones, I haven't heard of it being pre-installed on non-samsung phones.
I can't speak for the others, but the Samsung Galaxy Store does come pre-installed. However, Google paid Samsung for the Play Store to be the default action for app installs. So you get both stores and can pick which one you want.
That's just two options from two big players who cooperate, and only on some devices.
The Samsung galaxy store comes pre-installed on Samsung phones, I haven't heard of it being pre-installed on non-samsung phones.