It's still tough. They won't have the data used to train the model, which is an incredibly important part. There's a lot of existing competitors in this space with headstarts. There's no guarantee that the entire research organization will follow Sam even if they leave OpenAI - they're going to have a lot of offers and opportunities at other companies that have an advantage.
It's also not clear that this is a realistic scenario - Ilya is the real deal, and there's likely plenty of people that believe in him over Altman.
Of course, the company has also expanded massively under Altman in a more commercial environment, so there are probably quite a few people that believe in Altman over him.
I doubt either side ends up with the entire research organization. I think a very real possibility is both sides end up with less than half of what OpenAI had Friday morning.