Have you ever heard of Kang Shugui, a friend of the calligrapher? What about his calligraphy?

yes, it's collectible. However, the price of a calligraphy and painting will be different in different places, different times and different auctioneers. So it is difficult to judge, and it is not an absolute price; Besides, any personal evaluation is only one-sided and personal. Features, celebrities, and people who like them in particular may make the price higher. My own opinion, please forgive me for being wrong!