From the article “Japan needs foreign workers because of labour shortages. But if the conditions for long-term settlement become substantially more difficult, this could potentially reduce Japan’s attractiveness to foreign workers who are considering Japan as a place to build their long-term lives,”

Specifically, Japan needs workers in human services to physically care for the very large elderly population. They need them so badly that they are in the process of implementing easier work visas for them. But do you think those jobs pay more than the national average?

No, but that's the point. They don't want long-term residents, they want short-term labor. This has been the goal for a long time, and if you move to Japan expecting anything else you'll be disappointed.

"Labour shortage" is just the business's perspective on "plenty of jobs!"

If there truly is a shortage of outstanding jobs, then they can compete and raise salaries and the least significant roles ultimately won't get filled, which is optimal.