Ego? Can't admit we goofed? Same reason I stuck with my louse of a first husband for 7 years? LOL
Since I studied accounting I now know the principle of 'sunk cost' - you already blew the dough on something not worth it, so don't waste more money. Unload it for free or sell it.
Unfortunately I sometimes still spend time and money trying to make something which simply WON'T WORK become workable.
Pitch it!