Partially, but plenty of anime targeted at adults are also set in high school. Because japan romanticizes high school as, unless you go to university after, it is the last time before retirement where you aren't stuck in their hellish (but at least slowly improving) working conditions.

Very similar to the tweet in the OP really.

Personally even with the relative lack of free time i prefer working over being in uni, and high school was hell on earth that I only managed to cope with through video game addiction.