alt Hacker NewsClaude code amplified the trend hundred fold but there was already a significant increase of TUI since the days of go fzf, rust ratatui and python rich.
My bet would be a desire to do away with heavy browser based UI and the curiosity of trying to test the limits of terminal based rendering.
TUI is popular because a) there are no native GUI frameworks for simple tools that are easy, fast, and simple to develop in at the same time, and b) low fidelity lets you pretend being a UI/UX developer without really being one. The rest is abysmal. It's not automatable at all (the article is wrong on that point), less readable (monospace/no images), very limited (try making a DAW in it...), relies on a ton of ancient cruft in Unix-related terminals, it's not really portable etc etc.