Your guess is as good as mine.
I've been complaining about this crap since the DOS days, the overwhelming majority of people who ever bothered commenting about it every single time the topic comes up seem to agree (if with different degree of care) that the system is simply bad...

But Larian seems to be quite adamant about sticking to it no matter what and at best putting some stitch on it.
And what's worse, I can't remember a single time they ever acknowledge publicly that they are aware of the criticism or why they are so stubborn about it.

Party control in Baldur's Gate 3 is a complete mess that begs to be addressed. SAY NO TO THE TOILET CHAIN