What you say about the 60s (and even more so, the 50s) is true, Siegle. But there are still many modern cookbooks that follow that trend.
First, there are the "quick cooking" type books, put out by the likes of Sandra Lee, Racheal Ray, and others. The focus on these is preparing food as fast as possible, but quality can be secondary.
Next are what we've been calling organizational cookbooks. These are the ones primarily used as fundraisers by churches, fraternal and service groups, civic clubs, and so on. The bulk of recipes in those tend to be convenience-food oriented. But, like a gold mine, if you sift through a lot of slag there is solid ore to be found.
Lastly there are what I call "housewifey" cookbooks. These would be the Betty Crocker, Ladies Home Companion, and Better Homes & Gardens type, which tend to use a lot of convenience products in their recipes. They justify this by talking about their readers being busy housewives who don't have a lot of time to cook from scratch.
However, if you add all of those up, they are a small part of the cookbooks that get published each year. There are, literally, hundreds of them.
So, it isn't so much a matter of when they were published, as one's orientation. If you're a from-scratch cook, you choose cookbooks that cater to your outlook. If you are convenience-oriented, you choose those that satisfy those needs. And, if you're a little of both, the whole cookbook publishing world is your oyster.
It's important, too, I think, to have a good fix on the sort of cookbooks that appeal to you. Nowadays the average retail price of a hard-bound cookbook is 35 bucks. That's a bunch of money, for most people, and can lead to expensive mistakes---which is a compelling reason, IMO, to browse the bookstore and library shelves before making a purchase decision.