Practically speaking, being adequate at everything is as overwhelming as being great at everything. Different people have different things they consider essential. Some people consider self-defense essential; I would put sewing higher on the list. Overseeing a group of children seems like a fundamental skill, but I will never have the opportunity to learn it until the first time I need it. I don't have the genetics to sing, and I don't enjoy playing a musical instrument enough to make the hundreds of hours of practice worthwhile. Cutting my hair also has a learning process with unacceptable costs.
Basic social dancing: I took the classes, but they didn't stick.
Bushcrafting. Haskell. Fixing wiring in a house. Leveling ground. Driving a standard transmission. (I did it once twenty years ago, but presumably I could not do it again without instruction.)
Sharpening knives? I use my kitchen knives every day, but the guy at the farmer's market does a perfect job for practically no money.
Playing bridge: I don't even know why my brain thinks this is a fundamental skill. I don't know anybody who plays bridge. But, irrationally, it feels like one of the more important things separating me from being James Bond.
Ultimately you have to pick a small subset even of the basics, and I have a hard time seeing that big a difference between the realistic approach of learning a few things that are particularly important to you and not learning anything at all outside your profession. Sure, it makes sense to put effort into the things that are important to you. I know plenty about cooking, for example. But I still lack the skills to produce or maintain 97% of the things that are essential for my complicated daily life. Is there a big difference between 99% and 97%? Or even between 97% and 90%?
But now I'm thinking about sewing again. Someday....