Yi Seong-gye was the founding king, but his position within the Joseon royal family was ambiguous

Although he was honored as Taejo because he was the founding king, the figures primarily cited throughout the early Joseon period were Taejong, Sejong, and Sejo.
Yi Seong-gye received no significant mention throughout the early Joseon era.
It was later, during the reign of Sukjong in the late Joseon period, that Yi Seong-gye was elevated as a totem to strengthen royal authority.
Sukjong's objective was likely to establish the symbolism that he was the sole legitimate descendant of Taejo.
Seeing this, it seems that no matter how much of a founding king one is, if one is "devoured" by their son, they lose not only their power but also their symbolism.
On the other hand, Wang Geon was worshipped as an inviolable, sacred figure throughout the entire Goryeo dynasty.