Manufacturers rely on both raising the price and shrinking the product. The difference is, they know that consumers are price-conscious and consumers will catch the fact if that container of orange juice went from $2.99 to $3.39, and they will balk, they will complain. Maybe they will switch to another brand.
But they know consumers are not net weight conscious. They’re not going to notice, most of them, if the product has gotten a little bit smaller.