pragmaticjj

They obviously are not and can not be or become "top-tier males". That's the objective reality. They don't want to be part of the system as it has nothing in it for them.

In other words, their existence as part of the system is perceived as miserable as - if not more so - than being outside of it. So why bother trying?

There's very little to no return on investment for their efforts in improving themselves (or being part of the system).

If due to pressing economic circumstances they were forced to work, they would not be any less miserable, perhaps more so.

Shut-ins and NEETs are the last people you'd go to in order to improve demographics of any country. These are the people who generally avoid social contact much less talk to members of opposite sex.

I don't follow Japanese politics, but implicating NEETs in their demographic problems seems completely out of touch.

I don't see how this is relevant. Nobody is having babies in Japan, especially the shut-ins.

Immigration is "the simple solution" if the only thing you care about - selfishly - is that your retirement and pension benefits are being paid out.

It's a world wide phenomenon. While more pronounced in affluent countries with generous benefits systems, it's basically happening anywhere where supporting +1 person has marginal increase in costs.