As a baker I think that pre-made frostings from cans or boxes are an abomination.
And like the (zombie) OP it seems that frostings on purchased cakes have gotten “fluffier”, with a whipped cream texture. No body at all.
I make frosting from scratch for the cakes at work. It does have shortening, but it’s a firm shortening for baking use. There’s butter as well. I get a lot of compliments on it.
You cream together equal amounts of butter and a firm shortening. If you can’t get the latter, don’t, for the love of God, use Crisco, just go with all butter. Beat in an amount of powdered sugar equal to twice the weight of the fats, along with one teaspoon of almond flavoring for every pound of sugar. This could be a little stiff, so if it is, gradually beat in small amounts of light cream until you reach the spreadability you desire.
I’m always confused why frosting is so bad now, too. When I was young I loved cake and sometimes made a box cake because my mother worked and didn’t have the time. She’d explained that icing was simply confectioners sugar, a slight amount of milk to get the right texture, a teaspoon of vanilla extract, and a teaspoon of softened butter so the icing didn’t get hard. Add cocoa for chocolate icing. It’s so simple I’m surprised when other relatives always get frosting from a can. My mother’s way of making it may be unsophisticated but it’s still almost always better than what I’m served by others. And it’s very easy to make.
When I was a baker, we had two kinds - the fluffy stuff for cakes was called “cake icing,” and the dense stuff for doughnuts and pastries was called “roll icing.” We never used the word frosting.
Anyway, this is pretty much the recipe I’ve always used. Except I use room temperature milk instead of light cream. I think I also use less sugar, because I like my frosting less sweet.
