For the game to work out, everyone except for you needs to know it's a problem. Why else would any of the companions seek a cure? They all have massive personal issues to deal with that are a lot more important.
Well maybe act 1 in its entirety, at least how you meet the companions, is flawed, we WOULD need another reason for them to join us, maybe some companions would need their stories changed for it to work without the impending doom tadpole BS.
That doesn't make the current thing any less flawed, however, Larian had all the control they needed, it's not like they HAD to work with these characters, they could've just made different characters, different stories.
