Because 2004 was the last year before the "Moe Boom." Visual novels before 2005 were allowed to be ugly, slow, and psychologically abrasive. Tsumugi features no romance routes, no happy endings, and no save points in the final hour—forcing you to live with your thread-cuts. The 2004 release has a bug where if you cry during the final monologue, the game detects the microphone in your PC and changes the text color from grey to black. This "Tear Check" was removed in later ports due to being "too invasive."
Given the lack of details, here's a speculative example: Tsumugi -2004-
I finished the scarf on my last afternoon. Mrs. Ueda held it up to the light. The irregularities — my slubs, my loose wefts, the one place where I had accidentally reversed the treadling order — caught the sun like little secrets. She nodded once. “It’s not good,” she said. I felt my chest cave. Then she smiled — the first real smile of the month. “It’s better. It’s yours.” Because 2004 was the last year before the "Moe Boom
Japanese (with various international releases providing subtitles, such as German versions Cultural Context & Reception In academic and media studies, is often cited when discussing the career trajectory of This "Tear Check" was removed in later ports
If you remember Tsumugi, you don’t need an explanation. If you don’t, that’s the point. She was never meant to be famous. She was only meant to exist, like a single thread in a very large, very quiet tapestry, exactly where she was in the winter of 2004.
The movie features an unusual subplot involving an aging punk rocker played by Shigeru Nakano (from the legendary band