If they decide to collaborate with big poker network such as ggpoker, they have bigger chance to survive with the poker.
Betcoin and fortunejak or may betnomi, these 3 sites did try to have poker but all of them also failed although they have player base but I'm sure the number of active players are not as big as what we can see in Stake.
Your points are valid, but not all of those active players are interested in poker which is why it's still risky though Stake can definitely afford to take that risk considering how rich and popular they are.
What I find odd is that @Ahoy posted about it way back in May and there hasn't been a single update about it since then which makes me think that they probably abandoned those plans.