Thanks for that. So there are basically three things he mentions:

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".