To me, failed, implies some sort of real failure, not just, "eh, won't make us enough money" a la Google/business since forever/the exec who's pet project it was moved on/had babies/was fired for unrelated reasons/some other human thing unrelated to the technical proposition.
If, like, sea-water entered and corroded the system and it blew up and ate babies, and caused Godzilla, that would be a failure. It just being not quite interesting enough to go after seems... I mean I guess it is, but on a "meh" level.