yeah it could be multiple bottles of shampoo... but no who would ever say that in real life? "the shampoos are on the table"??? I mean it could come up if you're a shampoo saleswoman, but for the average person this is kind of an absurd introduction to the word
How On Earth Do You Count Shampoo? It's A Substance, You Can't Have "A Shampoo", Just As You Can't Have "A Water", "A Dirt", "A Sawdust", "A Tin", Et Cetera. Somebody Italian, Please Explain To Me Why There's A Plural For A Clearly Uncountable Word.