Did you read the article you linked? The store brands aren't saying they did it for taste, that is Robitussin (obviously full of shit, doing it to maximize profit or else they would've simultaneously increased the bottle size giving you effectively the same amount of the medicine just in a "better tasting" version - frankly I'm surprised someone hasn't made something like a beverage out of this stuff), who actually made this change 5 years ago in 2017. I'm guessing the store brands did finally follow suit due to "inflation" and/or "shortages". Which its a double whammy this year as I bet there are a lot more people buying this due to the uptick in respiratory illnesses this year, and those people are probably in for a bummer because of this. Its also further compounded by the fact that due to increased mass, some medicines are less potent already for modern American adults.
But it shows how you're much better off going with store brands for most medications.
Hopefully if things go back the other way people pay attention and don't overdose.
Also, frankly I'm surprised they didn't make the change by citing a concern for children saying that it helps prevent overdosing of them. I'm guessing that might've opened them up to proper scrutiny though.