But I'm not sure why they think I can't but the same emulsifiers etc online or at the local Asian grocery store.
1. Emulsifiers actually make the texture better
2. The flour they use has had some extra steps
3. They can use industrial machinery to smash their shortening and flour together in a way that's really not possible in a kitchen, that does make the texture better.
As someone else has said, it should in theory be possible to buy "better" flour; and you could buy emulsifiers, or use more egg yolk (which has a natural emulsifier), or use Crisco (which the video says has emulsifiers in it). So it's really the last one that's not easily replicate-able at home.
There is one thing he keeps repeating which I disagree with: "You're not going to be able to do a better job of engineering than the experts at Duncan Hines." Yes, both Duncan Hines and I are optimizing in part for taste. And I have some constraints compared with Duncan Hines: I don't have industrial grade machinery to mash shortening into flour; I can't experiment with and precisely measure an arbitrary number of potentially exotic ingredients.
But Duncan Hines has several additional constraints they're optimizing against which don't apply to me: They have to make it simple enough for an average person to make. They have to aim for a "median" palate. They have to make it shelf-stable for years. They have the pressure to shave pennies off the cost (as evidenced by TFA), which may mean (e.g.) buying cheaper chocolate or using a lightly lower quality fat than would be ideal.
So I disagree that it's a given that Duncan Hines' cake mix will be better than something I can make from scratch.
I will, however, concede that there are reasonable advantages to using a "commercial base".
Adam Ragusea did a piece on the differences awhile ago:
https://youtu.be/CZDFwqHkPec
Boxed mixes came out of the same "scientific foods" fad in midcentury America that gave us things like Jello.