Jung Bong shouldn't have been characterized as someone who takes his passion for food to start a restaurant. He loves eating and snacking but throughout the show we see him nerd out over video games (among stamp collection). He's said to be super competitive (on the same level as Taek) and we see so many scenes of him playing at the arcade. Considering he was also a sickly child, and what w Jung Hwan making his brother's fantasies (football, basketball, pilot) as his own dreams, Jung Bong's career path should have been written as a game developer. The show heavily references the economic policies that allowed American exports into Korea. The first McDonald's is a celebrated occasion. The Nikes and Addidas sneakers are cherished and in high demand among the students. The denim fashion, the music, posters of Michael Jordan and Jackson, the Stevie Wonder and Wham! songs - the entirety of Reply 1988 reflects this influx of American culture and influence. So why not video games? JB taking his passion for gaming to the next level by becoming a game developer, influenced by the popular video games of the 80s and 90s America makes more sense than starting his own restaurant (and let's face it: the writers adding his cooking skills and descriptions of flavour profiles in the third and second to last episode was such an obvious retconning attempt to justify his choices in the last episode). And for a sickly child who stayed indoors all day, gaming as an act of escapism and living out his fantasies was a perfect character conclusion (he had the money and connections and he's always been someone on top of the latest technologies).
There was already a character who started his own restaurant, Dyong Ryung (a decision that makes the most sense for a character progression in all of Reply 1988 - will explain in another post why) Why add JB, a compelling character in his own right, to that list unless the writers really just wanted the show to end and didn't care what happened to his arc, which frankly explains a lot about the time skip episodes.