But a survival show doesn't guarantee success anymore. Especially with GGs.
We've seen this with Fromis_9, Kep1er, and CLASS:y. Also wouldn't doubt if this new Queendom Puzzle group flops. They might sell more than Fifty Fifty, but that doesn't guarantee public recognition/support.
I honestly wouldn't call any of the groups you listed as flops. Excluding Cupid which was a viral hit, all those groups you listed are doing far better than Fifty-Fifty in every single area, Fromis_9 and Kep1ler especially. Also, Queendom puzzle is a different class of survial show and can't be compared. Queendom puzzle is along the lines of The Unit: shows that bring back old faces and failed idols, which obviously will never do well as shows like Produce48 that introduces young fresh and talented faces.
But even then, the industry professionals are enough to counter your claim that survial shows don't do well. If survival shows weren't successful then why are companies (even big ones like HYBE who shouldn't even need survival shows with their level of brand recognition) announcing the start of a new survial show every other day? You listed Queendom as one example of a failed idol show but neglected to mention the (many more) successful ones,
After NiziU, JYP is already doing A2k right now. Zerobase1 just had the most successful debut of all time after being on Boy's planet, after I-Land that brought us Enhypen, HYBE is just about to wrap up RUNext and will immediatly be starting Dream Academy, plus they already annonced to be in another partnership for a new girl group with SBS (?). Oh, and let's not forget even &Team was formed on a survival show in Japan.
If Attrackt does team up with Mnet, the Fifty-Fifty scandal is big enough that many will tune in, some for the drama, some out of curiousity, some just to hate watch, and some because they are survival show addicts. And all it takes is for a single trainee to catch their eyes and then it's over.
And even if Fifty-Fifty 2.0 only does as well as Kep1er, that is still leagues better than the Fifty-Fifty now, because at least they will have an actual fandom to support them once Cupid starts to decline and listeners move on.