Of course they aren’t.
The eggs are in the refrigerator (unless a really fresh one from the henhouse is being used). The flour’s probably in a cupboard somewhere along with baking soda, vanilla, and other dry ingredients. The bowls, spoons, pans, and the like are probably in their own separate places as well. And there’s the oven and a cooling rack. Depending upon how many people have immediate access to your cookies, storage may not even be a problem.
You wouldn’t limit your cookie preparation to things that were in the refrigerator. In a similar fashion, you shouldn’t limit your genealogical research to the internet. You need things in other places in the kitchen and shouldn’t look in just one place.
There are libraries, courthouses, cemeteries, and other repositories. Even for research done online, limiting yourself to one or two sites would be comparable to looking on only one shelf in that fridge. What you want may require looking on another shelf–after all people sometimes put things where they don’t belong. That also happens in libraries as well.
It’s not all online and it’s not all on one site–no matter what the advertising or your cousin says.