No, it's industry standard to advertise the total internal storage, not the free storage that's available to the user -- and yes, this is the case even for iPhones. Some devices have more bloatware than others, so it's worth doing a little research before you decide on one.
And no one ever advertises that you can expand your storage for app installation with SD cards, unless it's a Marshmallow device that supports Adoptable Storage (and LG, along with Samsung, decided not to implement this feature).