The thing is, there is no hive mind called "society". Everybody works in their own interest. Always, and in every "society".

Individual workers work on failing initiatives as long as they get paid. The outcome of the initiative may be bad for "society". But was it good for the individuals working on it? Maybe they got paid well. Maybe they enjoyed the work? Maybe the work was easy because they knew that it would fail anyway, so they didn't have to put much effort into it?

Maybe it was also good for the management or politicians? Maybe it was a step up in their career. And maybe, if they could jump ship before the failure became obvious, they could climb up the ladder to get to an even better position? You can always blame your successors for ruining the project.

And maybe it was good for whoever ordered it? If it's a local project, maybe they got subsidies from federal government bodies, and they don't even care whether it succeeds, as long as it created employment and the illusion of progress? Or if it's a private project, maybe they just tried a moon shot that, if it fails, was useful as a tax write-off?

In real life, there are so many layers to a 'failed' project. It can be a failure for some and a success for others. And those for whom it is a success will defend it, maybe even deceive to keep it running.