It is a reflection of an actual problem in Japanese society; with the low birthrate, it is fairly commonplace for adults to live with their parents until they are married, well into their late twenties or thirties.
Unfortunately, with so few ready career employment options available, many in this position remain in education or are underemployed for a comparatively long time, and around 3-5% are neither employed or in education.
We are seeing shades of the underemployment and “over”-education issues in the west, but in Japan, “living in your mother’s basement” is not a derogatory comment; it’s both expected and the norm.
I think it is a bit overdone and somewhat of an example of pandering to an arguably significant part of the anime fanbase but pretty much everything is if youve watched enough anime.
I'm waiting for the day some anime producer is brave enough to make the anime equivalent of , it would be pretty fun to watch since the anime industry seems to be too afraid of actually drawing an overweight character.
Also, not even Charlie (The Whale's protagonist) is a NEET.