Here’re the details from the movie I remember:
* I watched it in the nineties-two thousands, the comedy could be from the 60-80s. Colored, the time shown is also around 60-80s.
* A Japanese family of 4 lives in a tiny apartment(most likely Tokyo). Father, mother, two sons. The parents are around 40-50 years old. Both are short and roundish. Younger son is shown to sit on a toilet all the time reading comic books, the apartment only has one. In the beginning he’s shown on the toilet, reading, while his older brother is banging on the door yelling he’s gonna poop his pants.
* At some point they see a TV commercial of a reality show where the winning family will be given an amazing big house with all the modern amenities to live in but their life will be televised. The family enthusiastically joins the contest and wins. During the interview they’re asked if they love each other and to prove it the wife cheerfully kisses her husband in front of everyone much to the shock of everyone.
* They move in to the new house and at first everyone is happy. The comic reader gets his own toilet where no one bothers him.
* The husband starts experiencing issues at work – a co-worker approaches him and tells him that since he’s such a celebrity he must use his new fame for the good of the firm. He also tells him that even his boss doesn’t have such a house. So he gets transferred from an office desk job to advertising some kitchen mixer they manufacture in a shopping mall. He’s bad at it and the mixer is shown malfunctioning in his hands during presentation.
* In the end they decide to give up the new house to go back to their previous peaceful life and the wife is shown playing with the window shutters by pressing buttons making them open and close.
https://www.reddit.com/r/japan/comments/11a6tmt/i_wonder_if_anyone_would_help_me_identify_an_old/