Calligraphers' handwriting is so valuable, why not write more?

That thing which is rare is dear. If you write too much, the market will flood, and no one will want to spend a lot of money to buy it. In addition, calligraphy is also an artistic creation, which requires inspiration and creativity. Calligraphers can not create every word successfully, but also represent their own level. Unqualified and defective calligraphers will not sell them, which will affect their reputation. Therefore, even if calligraphers write a lot, there will not be many qualified and high-level words, so they give everyone the impression that calligraphers don't write much.