Question

we can save songs and regain it why we can't save smell and regain it

Answer 1

who says we can't regain the smell we can like for once if uh smell lilac and next day if u pass by lilac garden then uh can remember it again

Answer 2

You actually can regain the smell. Suppose there's some flower or food whose smell you really liked, them when you think of it, you will get the smell. The same happens with taste, sound and even sights.