There's this quote that is attributed to Bruce Lee that goes something like,

I don't fear the man who has practiced 10,000 (different) kicks, but the man who has practiced the same kick 10,000 times.

Another way to state this—it is better to be very good/effective at one (simple) action than to add confusion and variety prematurely.

Economists will talk about scarcity. We have finite time, attention, and resources and so on. Now, if you get better at doing some one action, it becomes cheaper and cheaper to do. You can beat out all your competition doing that one action. In lots of RPG-type video games, characters have "skills". In many, many games what you do is "max out" one single skill first rather than distributing your skill points broadly across many. In playing the game, your one powerful skill will drive your play style. As you progress through the game, you will probably use more than one skill (otherwise the game would get boring), but the general principle still applies—it is important to get very good at one thing at a time. You might be able to do the "bare minimum" for some other things to have more options, but it will be your strong skill(s) that really do most of the work for you.

Continuing on this RPG game analogy, your character will probably have stats like "STRENGTH", "INTELLIGENCE" and "DEXTERITY". In a typical game, different character classes will make use of different stats. So a swordsman might have very high strength and some dexterity whereas some kind of wizard/magician character won't need very much strength. Does this idea apply to "real life"?

Insofar as our bodies are concerned, I think this does apply. For instance, if you train a lot of upper body strength, this may be helpful for swimming or chopping down trees with axes. However, this will add extra weight for a long-distance runner that doesn't help with long-distance running so much. So our bodies can "optimize" to fit particular activities we do. Likewise, people necessarily have to focus on learning different things—if you want to get good at playing guitar, you're going to have to decide whether or not you are right or left-handed first. Then you train your right hand to do certain things and your left hand to do other things. Coordinated together, you make music. But your knowledge is tied up in your body. If you flipped your instrument upside down and reversed your hands, your knowledge wouldn't be able to instantly transfer/manifest itself in your playing.

This is why it is important for us to do and to practice and not just have "head knowledge" about how stuff works. "Idle knowledge" is knowing how to do something—e.g. learn another language, but then not doing it. Most of our hours should not be spent in just "learning" (like attending class, learning theory), but in the practice of activities whereby our theory becomes something that can affect change on the spaces around us.

Computer Mediated Action

Computers (and software, more broadly) are complex tools that mediate our actions. Whereas writing a letter by hand on a piece of paper is pretty direct, the convenience of using a computer comes at the price of fitting everything to the form that a machine likes.

One could argue something similar is going on playing a piano vs playing a harp; the machinery itself constrains the types of actions that can be done. Loss of control in certain areas allows more efficiency or options in others.

As tools themselves become more complex, we see a lot of off-loading of "skills" to machines themselves. So rather than skills, but knowledge of what to do becomes important for doing more.

Since we have computers, lots of people do a lot less handwriting. Many people feel awkward/uncomfortable writing by hand because they are so accustomed to typing on keyboards—or even more abstract, using the input methods of things like smartphones and tablets.

Is this a problem?

Insofar as our tools behave as we expect them to, then there isn't a problem. However, what I have noticed is that when skills are highly dependent on a very delicate/particular arrangement of stuff, you can quickly find yourself in trouble if you don't have more basic/fundamental skills. For example, very specialized knowledge in one programming language (say, FORTRAN) can allow you to work very effectively on systems that use that language. However, you will need a lot of time to get "up to speed" working on a new system. Working in a whole different domain entirely will require even more specialized training. So a scientific computing FORTRAN expert will not readily be able to do PHP web programming.

If all the computers went down for some reason, there would be even more trouble.

This is the trouble with a lot of "high tech" learning. Relying on specialized systems too much means humans forget how to do that one kick that Bruce Lee fears and instead turn us into 10,000 different kicks people who don't really know that they're doing. Dissipation of energy and attention!