Concorde fallacy
noun[S]
ECONOMICS,MANAGEMENTukustheideathat you shouldcontinuetospendmoneyon aproject,product, etc. inordernot towastethemoneyoreffortyou have already put into it, which mayleadtobaddecisions:
The Concordefallacyrefers to thefactthat the British andFrenchgovernmentscontinuedtofundtheaircraftevenafter itbecameapparentthere was nolongeraneconomiccasefor it.
Compare
sunk cost