Why don't supermarket cakes have that familiar scent anymore?

[SupermarketCake]

Ever since the ban on partially hydrogenated oils in 2018, the supermarket cakes (particularly the chocolate cakes with chocolate frosting...I don't remember whether the vanilla varieties had the same scent, as I haven't eaten as many of those) no longer have that overpowering scent they used to have (which was my favorite scent in the world...save the culinary snobbery, not interested).

What's the reason for this? Did the oils being partially hydrogenated rather than fully hydrogenated really affect the scent that dramatically, or might they have changed something else when reformulating stuff? It's hard for me to believe just changing the hydrogenation of soybean, cottonseed, and palm oils would change the scent from overpowering to close to nonexistent.

I want to try to recreate that scent on my own, but I haven't had any luck with what I've tried so far with mixing frostings. I figure the frosting is likely the main thing responsible for the smell, but maybe I'm wrong?

 

[retired baker]

do they even bake in those stores, I doubt it.
If they do its going to be from bagged mix.