Blessed is the person who decided to exclude recipes from copyright law. They will forever hold a place in my heart.

That’s a limitation of your source. Several recipes that I’ve seen passed down from that era were like this. Many of those recipes have an origin that can be googled.

I am an accomplished cook and I have a lot of recipes passed down a century or more first-hand. Many have the property I described. I know many other people with similar family recipes.

Just because you’ve never heard of it doesn’t mean it doesn’t exist.

Most of the product types you're describing didn't meaningfully exist until the 50s (which is why I used that era) as WW2 greatly expanded production of crap food and subsequently led to a wider public introduction. So having family recipes using them from a century or more would be quite odd.

Beyond that, what do you think is more representative of recipes of the past? A selection of hundreds of recipe books with thousands of recipes, or the family recipes of yourself and some acquaintances?