Upvote:1
The answer seems to be included in your question. Rongguang Zhao explains in "A History of Food Culture in China" (p.18):
Put another way, eating habits shifted from sitting alone on mats to sitting on chairs around a table. This made using shared dishes practical. And after coexisting for a while with individual dishes, shared dishes eventually became the norm.
(This arguably doesn't answer a related question, namely why they decided to move to sitting around a table to begin with. For added comfort or because it became more affordable to do so, perhaps?)