I don't know what's your experience with k-dramas, but stupid plot points is almost a requirement. What you are talking about producer doesn't sound that bad though. It's fiction, it doesn't need a precedent. The closest we have been of some company burying an idol or forgetting about someone was YG with se7en. The guy just disapeared after the massage parlor scandal until his contract eventually expired.
Edit: Although, now that I think of it, the most recent case of replacement didn't involve and individual but a group: Red Velvet replacing f(x) after the Sulli thing. I hope that I'm wrong, but until proven otherwise, it seems like that's going to be the case.
Yea I have watched quite a few k-dramas, just that I take Producer as an exception, being a variety drama with real-life elements moreso than others, multiple cameos/mention of other idols/agencies (JYP, YG, SNSD, EXID, Suzy, Dara etc) even if they come with a faked personality.
How big was se7en though? Cindy is described as a "Top Star" who has consistently been winning #1 on music shows during her album promotions (even winning with a ballad), has Suzy as her CF rival, has constant 10k+ sold-out concerts in Japan etc. The scandal Se7en had pretty much counts as a sex-related scandal (which is pretty damaging for a scandal in Korea), compared to the one Cindy had which seemed more likely to get fan support rather than the hate that was shown, not even counting the illogical part with "CEO Byun knew nothing about it/never met her parents" because you know, a minor signing a contract without parental approval is just impossible.
Not sure how RV is replacing F(x) since they have rather different fandoms still, and the member composition isn't even similar. Like, even if someone argues that EXO has taken over SUJU's position as the main boy-group of SM, its not like ELFs automatically switched to stan EXO instead, fandoms don't work like that.
I think the point was not that she's replaced because she's losing steam (possibly unlike Yuna), and Byun CEO was forced to rush her plan, as Cindy started thinking on her own.
Again the drama, for understandable reasons, showed an extreme example, but the real life equivalents are more like big stars being given gradually less push and sometimes dropped from labels.
That's the thing though. I mean, for example, sure, BoA is now barely promoted by SM since they are spending most of their efforts on EXO and maybe Red Velvet (letting SHINee do their own thing), but its not like they ever did this during BoA's peak. No company is stupid enough to do this, but Byun CEO is shown doing exactly that (forcing a scandal right after a very successful promotion over one incident...yea no). Now add on the "I can easily replace you" thing and it really requires quite an imagination to even consider that scenario plausible in the current k-idol industry. Even JYJ has survived well enough for the 7 years of broadcasting ban they have endured, I don't see how a Suzy/IU level idol not survive with the fanbase that they have over such a low-impact/illogical scandal.
I don't mind a little exaggeration, but within context of the "variety drama" laced with real-world idol elements, even that seems a little extreme/unbelievable in comparison. Just changing the scandal to something more serious would have made the scenario more believable IMO (ie Cindy caught walking out of a man's apartment!).