If he really didn't care, wouldn't it have been easier and more effective to only publish on the arxiv, and perhaps to tell people working on the problem about his solution?

He did publish it on arXiv

> Not knowing LaTeX, the word processer of choice in mathematics, he typed up his calculations in Microsoft Word, and the following month he posted his paper to the academic preprint site arxiv.org.

If you're old and don't know LaTeX? Probably not, especially since he was an editor with the journal he published in.

Sounds like a bullshit excuse. I don't understand why anyone would even argue that they intentionally do a poor job presenting their work because they somehow allege they are ignored.

The only reason why anyone would go through such pains to get ignored is if they intentionally want to be ignored.

And this does not make any sense, particularly in a "publish or perish" environment.

I on the contrary find it perfectly reasonable. Academic publishing has its own share of bullshit and I can well understand someone, specially a retired person, wanting to give up on that kind of prestige in order to save time and energy for actual science. For example, as far as I know, Grigori Perelman has not published the work that won him an offer of the Fields Medal in any journal.

It is clearly stated in the article that Thomas Royen just wanted to get published quickly, as he isn't an academic.

I sympathize, after getting my PhD I went into the private sector. I often have side projects that could turn into publications, but massaging something through the publications process is a part-time job itself, and there's definitely quite a bit of who-you-know that can muddy things up.