People do still like big screens, many people have them at home. They just struggle getting a 60" screen in their handbag or pocket.
Technology has been progressing forever, now is just a small chapter of a story millions of years old.
How would any generation cope without the things they grew up with and take for granted. Imagine being without electricity, running water, motor vehicles, going back further, industry, agriculture, the wheel, buildings as opposed to caves, fire…
There were past generations that went without all this and got by, as they didn’t know any different. Now we have them, take them for all granted and wouldn’t have it any other way.
People in the future may look back at us and think: How did they live like that? Without XYZ futuristic thing. Every generation throughout time lived in the modern age from their own perspective. What they had then was cutting edge.
2 and 3 column designs are still possible as part of a responsive design. There is no reason that your desktop view of a site should look any different regardless of whether it is responsive or not.
You can keep exactly the same design and layout in a responsive design. How it works is that the changes occur only on the smaller screens when the big design no longer works. (if you take the desktop first approach, which is probably most appropriate for you)
The sooner you lean RWD and start to understand it, the sooner you will stop flapping about it, then wonder why you were getting so wound up.
The best thing you can do is find some learning resources (lots on-line), then open your editor and get coding. When you get stuck, just ask.