Was the Xia dynasty mythical?

According to the first general history book, Shi Ji, the record of Xia is clear as the record of Shang Dynasty. The discovery of Oracle and Yin ruins proved the existence of Shang. It is true that there is lack of evidence to prove Xia. Mostly, we believe there was Xia Dynasty.

The Erlitou culture was found by Chinese archaeological scientist at 1950+. they used modern technology to improve The Erlitou culture and Xia Dynasties at same time in same area. So they believe The Erlitou culture is Xia Dynasties.
However, they do not find any written language from Xia Dyn, the earliest written language just from Shang Dyn.
anyway, The first general history book has clearly record about Xia Dny, that' why chinese believe Xia Dny.
About Xia Dny is a mythical.