Just as headphones have not supplanted speakers, neither will VR headsets replace monitors. What is being done in developing VR, will push forward monitor technology drastically too though. In the near future, aside from content continuing to scale up in resolution, displays following along to grow both giant and small, we'll begin to see other changes develop. For example, even now while 4k is still basically new, we're already seeing development of UHD standard, and even 8k is already on the table.
On top of that, we're also likely to see developments in glasses free 3d, and far better in tv enhancement of the image to both a higher resolution, and 3d, from native, lower resolution content
All this technology is interdependent though, and in it's infancy. No different as I see it, from where we were with smartphones. Blackberry, the first good (yes there was the palm, and some others, but they were never widely adopted) smartphone came about to the consumer market more or less in about 2005, and hit a peak in again, imo, around 2009. The very first models were in use around 2000 already though, which is where we're at now with VR. Now, less than 20 years later, phones are less phones, and more portable computers.
In terms of practical applications, there is really no end to them. Already we have doctors performing surgery remotely, and with VR these application will take a huge leap forward (there are surgeries you can watch in 3d already too!). Any application for remote access and control becomes far more manageable.
In construction, and planning, AR would help immensely. How often have you driven by to see a guy painstakingly measuring things out with a tripod setup, a rangefinder, clipboard? Hour long surveying jobs could be done in minutes. AR would also help in long range interactions, and where we now have video conferences, in the really not far off future we will have VR conferences, where donning a headset will allow you to see a person sitting in your office, and for them to see you in their livingroom.
Entertainment and therapy options abound too. People who have common fears, and anxieties could expose themselves in completely controlled environments.
On a more basic scale, I'm looking forward to a not at all far off point where I'll be able to have a virtual office, while at the office, with completely privacy when I choose it, and still the ability to directly interact with colleagues when needed.
Art will also absolutely take off as 3d printing and 3d designs merge together. Really really endless possibilities.
A breakthrough that's needed to push the envelope even further is some form of tactile feedback, and feedback for our other senses...