The mystery keyboard - what was the message?

Inspiration for this puzzle

Here is a picture of my actual computer keyboard. I posted it here originally. https://lifehacks.stackexchange.com/questions/23760/i-like-my-computer-keyboard-but-the-letters-have-nearly-worn-off

As you would expect, letters are worn pretty much according to the use I have made of them. Also worn but not shown are I, O, H, L, and N.

Background

A typewriter-repairman receives an old model to be renovated. At first glance he recognises it to be an Adler from the 1960s. The typewriter has the ordinary English, QWERTY keyboard of the day. All key tops are in the correct position.

Then he notices something very odd. He is used to seeing wear of the keys in certain places. These are approximately as shown in the above picture.

What he sees is a very different pattern of wear. The following shows the amount of wear for each key starting with the greatest.

1. A - (most wear)
2. L
3. K, O
4. D, N, Y
5. B, C, E, J, M, P, R, S, U, W
6. All other letters no obvious wear

He doesn't concern himself with the space bar, shift key or punctuation keys.

Question

Can you explain this unusual pattern of wear? What was typed? Who can you expect to have owned the typewriter?

Notes

1. It is always difficult to estimate the difficulty of one's own puzzles. Someone may have a lightbulb moment with this but, if not, I'll add more clues one by one.

2. You can assume that ordinary English dictionary words were typed, separated by spaces in the usual way.

3. You should be able to explain all the facts I gave under Background. Nothing about the typewriter is irrelevant or arbitrary.

• Is the part before the background (specifically, the letters worn on your own keyboard) relevant to the answer? Aug 29, 2020 at 21:40
• @Shubham Goenka - It is relevant only in the sense that it shows the sort of wear that the repairman would normally expect, having renovated or repaired hundreds of typewriter keyboards. It shows why he would be surprised when he saw this latest repair job. If it helps, you can assume he didn't repair computer keyboards - only typewriters. Aug 29, 2020 at 21:43

The owner of this typewriter was

Jack Torrance from the movie The Shining

and has been

failing to write a play, instead typing over and over again "All work and no play makes Jack a dull boy".

I wanted to

start this answer with "This is a shining example of ..." but couldn't find a witty enough continuation that didn't give things away.

• Too quick! For a bonus point, can you identify the exact model of typewriter? Aug 29, 2020 at 22:22
• A bit of image-searching suggests it's an rot13(Nqyre Havirefny 39). Aug 29, 2020 at 22:43
• Correct - How would you like to receive your bonus point? ;-) Aug 29, 2020 at 22:44
• I think a virtual bottle of ЯED ЯUM would be an apropriate bonus reward :) Aug 30, 2020 at 6:45
• Very good! Maybe even ЯEᗡ ЯUM? Aug 30, 2020 at 13:08