I feel like some of that is just branding efforts. Lots of food companies will put their brand onto the soy sauce/butter/whatever that they are promoting when writing recipes and those get copied.

But while you can talk about reproducibility etc, at the end of the day the amount of variation between various brands of canned pumpkins are less that the amount of variation _you_ should consider when making a recipe to match the tastes of those you are making it for.

We have plenty of foods we make at home where we routinely just look at the base recipe and decide "that is too much/little salt/sugar/etc" and we are happy in the end. Harder for baking tho.