Functionality
Everything we use has a purpose. Human gadgets are a direct evolutionary extension of our basic and not-so-basic needs, be it food or entertainment. Hence, if something exists, it exists for a reason, or it stops existing. Sometimes, the shape and usage of tools is dictated by technology, but the functionality does not change. For example, killing people in medieval times was done using different tools than today, but the actual purpose of tools at hand remains.
Likewise here, humans need to interact with software in some way. There are many possible ways this can be done, including touch, voice, eye contact, and other sensory inputs. At the moment, the most prevalent technology is touch, having transformed from manuscript to typewriters to digital keyboards, with some usage of the mouse as a pointing device.
Keyboard
The keyboard seems like the most primitive of these tools, being very little different from the good ole typewriter, which hails back at least 150 years. However, there is a very basic, anatomical reason why we use keyboards, why letters are placed the certain why, and why keys are of a certain size. Which is why the advent of technology has not affected the typing functionality that much.
Some people are calling for the transformation of touch, from using a typing device like the keyboard and a pointing device like mouse, to a pure digital experience. In a way, this kind of makes sense, right. You replace one type of technology for another, while offering users the same functionality. The best example would be the wheel. It powered carts thousands of years ago and it still powers supercars like Bugatti Veyron. So the same logic should apply when you go from physical keyboard to touch, right? Well, not quite.
Humans have always written text from a sitting position, on horizontal surfaces. Before computers, the position of text was in line with the written manuscript. Typewriters separated the input and output, creating a revolutionary concept that we know as blind typing. It allowed us to have two dimensions to our alphabet experience, one where our hands remain horizontal, the other where our eyes could be positioned more naturally.
So we went from horizontal-horizontal to horizontal-vertical, and that was the big leap, which enhanced the experience. The proponents of modern touch only bullshit call for using vertical-vertical, or again, horizontal-horizontal. This is a dramatic change in how humans interact with text. Either way, it is a regression from a two-dimensional space into a one-dimensional form.
Therefore, whether we will have keyboards vs. touch is irrelevant. The only question is, will humans accept this regression? The answer is quite simple. They will not, because it goes again the need and purpose behind the technology. Indeed, if you look at this from a different angle - you will be more productive typing on a physical keyboard than a virtual device.